You'd have a pretty hard time of it if you tried to make the case that The Big Bang Theory is actually a romantic comedy. Sure, there are central couples in the series that viewers have been expected to root for all along, and there are plenty of romantic moments along the way, but nothing about the series as a whole screams that this is a show about romance -- or, for that matter, people who are any good at understanding what it means to be in a relationship and to love someone.

Leonard and Penny, Sheldon and Amy, and Howard and Bernadette were all lucky enough to find one another and attempt to make things work as a married couple, despite their own many, many differences. Raj, the most hopeless romantic of the group, is still desperately seeking the right one before the series ends. However, along the way, all of these characters showed, time and again, just how difficult it can be to find someone who understands you -- and often through spectacularly hilarious failed attempts at relationships.

Whether one of Penny's brief relationships, Leonard's overbearing girlfriends, Sheldon's bizarre admirers, or Howard's less than savory secret relationships, The Big Bang Theory has explored its fair share of relationships we could've done without -- but also, along the way, hinted at relationships that could've been more, but were sadly dropped.

Here are the 20 Couples The Big Bang Theory Wants Us To Forget.

Leonard and Leslie

Leslie Winkle and Leonard Hofstadter in The Big Bang Theory

We can understand where this couple came from, even if we don't necessarily support it. Sara Gilbert recurred in the early seasons of The Big Bang Theory as Dr. Leslie Winkle, one of the guys' colleagues at Caltech, and eventually, she hit things off with Johnny Galecki's Leonard. Their relationship didn't last long, but it was a key one for Leonard, as it allowed him time to move on from his infatuation with girl next door Penny.

The relationship likely only ever happened, of course, because Gilbert and Galecki spent years together as Darlene and David on Roseanne. Playing into the nostalgic factor with fun casting is fine when done in moderation, but Gilbert's Leslie never really fit in the series, and she and Leonard were just entirely wrong from the beginning.

Raj and Lucy

Raj Koothrappali and Lucy in The Big Bang Theory

Poor Raj. Despite being arguably the most truly romantic and hopelessly romantic member of the group, he's never really had any success in the romance department. He's had his fair share of relationships over the years, but none of them have been the right fit. The first to fit into this category was the relationship he had with Kate Micucci's Lucy -- a hopelessly awkward and anxious girl who snuck out of a restaurant window to get away from a date with him.

It seemed like maybe they could find some common ground -- Lucy preferred communicating via text messages, which made things easier for the once anxious about speaking with women Raj -- but in the end, nothing about this relationship worked, and Lucy left the series.

Stuart and Penny

Penny and Stuart Bloom in The Big Bang Theory

Stuart is another character who's had a hard time of it in the romance department. Recently, he seems to have maybe found the one with Denise, a fellow likeminded comic book addict and expert. However, in early seasons, Stuart once tried his luck with Penny. It was an unexpected pairing to say the least -- particularly when the back and forth flirtation between Leonard and Penny was at an especially fraught point in the series.

However, toward the end of the second season, Stuart and Penny went on a few dates and seemed to be getting on well enough -- until suddenly, while kissing, Penny said Leonard's name, instead of Stuart's. The relationship pretty much fell by the wayside from that moment on.

Amy and Bert

Bert Kibbler and Amy Farrah Fowler in The Big Bang Theory

Bert Kibbler is a character The Big Bang Theory has sadly underutilized ever since his introduction. The adorably geeky geologist was once offered as a potential love interest for Amy, and though it was clear that things wouldn't work out long term given the series' clear agenda of securing Sheldon and Amy as a main couple, the brief connection the two made with one another was adorable.

Bert appreciated Amy and respected her in a way Sheldon occasionally struggles to do, due to his own ego. He frequently brought her gifts and told her that she was the coolest girl in the entire school. However, sadly, his affections weren't returned, which left him alone and forced to deal with his unrequited feelings.

Leonard and Priya

Priya Koothrappali and Leonard Hofstadter in The Big Bang Theory

Dating one of your best friends' siblings is really never a good idea, especially in a show that operates like a comedy of errors in the way The Big Bang Theory does. However, for much of season four, Leonard does just that when he dates Raj's sister, Priya. Priya is more serious than any of the main characters, often condescending toward their interests, and truly just a poor fit overall for the series.

Her relationship with Leonard is hardly any better or warmer than the frosty reception she receives from his group of friends. They are often at odds with one another, and her character seldom serves more of a purpose than being a way for Leonard to make Penny jealous -- which really does none of the characters involved any favors.

Sheldon and Ramona

Ramona Nowitzki and Sheldon Cooper in The Big Bang Theory

It may have taken a long time for Sheldon to develop a real romantic and physical interest in women, but that certainly didn't stop him from acquiring his fair share of admirers over the years. Perhaps the most notable -- and most aggressively forward -- of these was Ramona Nowitzki, a fellow at Caltech who served under Sheldon's advising and quickly became infatuated with the scientific genius.

Sheldon never returned Ramona's interest during her brief tenure in the series, but when she returned years later, that didn't stop her from pursuing him even more aggressively -- despite his serious relationship with Amy. The only thing that came of her kissing him was Sheldon resolving to propose to Amy, so it's safe to say this relationship was never meant to go anywhere.

Mary and Alfred

Alfred Hofstadter and Mary Cooper toasting in The Big Bang Theory.

Another relationship that never really went anywhere -- but definitely should have -- was the briefly teased romantic connection between Sheldon's mother, Mary Cooper, and Leonard's father, Alfred Hofstatder. As portrayed by sitcom legends Laurie Metcalf and Judd Hirsch, the duo practically sparkled on screen together, and wound up spending the night together, much to Sheldon's and Leonard's respective horror.

The prospect of Sheldon and Leonard surprisingly becoming late in life step siblings was one the series didn't do nearly enough with. It was implied that Mary and Alfred would be continuing their bond, but Hirsch never returned to the series (likely due to his commitment to the now canceled series Superior Donuts), and no mention has been made of their time together since.

Penny and Kurt

Penny has had her fair share of bad boyfriends, but arguably one of the worst of them all was Kurt, the total jerk whom she was dating when the series first began. Penny and Kurt spent four together, even living together, but Kurt eventually cheated on Penny, leading to a particularly bad separation. Despite this, Penny found herself going back to him time and again during the first season, even when he spent much of his time antagonizing both Leonard and Sheldon.

Kurt was never much of a character beyond being a bully and a pig, so it's a shame that the series felt it necessary to keep Penny tied down to him for as long as it did during the early formative episodes.

Howard and Leslie

Leslie Winkle and Howard Wolowitz in The Big Bang Theory

Leonard and Leslie's relationship is one that we can force ourselves to accept, if only because of the behind-the-scenes rationale for it. However, the idea to pair Howard and Leslie together in some sort of uncomfortable, friends with benefits but more like frenemies with benefits scenario was a decision that the series would have been much better off avoiding.

It never seemed like the two characters particularly liked each other in any way, which made the awkward relationship uncomfortable to begin with. However, making matters worse was that Leslie essentially extorted Howard throughout their dysfunctional relationship, as she was in a position of power when it came to handling the allocation of funding for certain projects of Caltech.

Raj and Penny

The Big Bang Theory Raj and Penny's Night Together

Much of Raj's character was once defined by his inability to communicate with women unless he was completely drunk. Much of Penny's character was once defined by her absolute love of getting drunk whenever possible, within reason. Thus, it wasn't that surprising when the two characters wound up falling into bed together at the end of the fourth season, but that didn't mean it was that great an idea, either.

It made for a few moments of awkwardness among the group, especially since the pair were semi caught in the act as they tried to sneak out of Sheldon and Leonard's apartment, only to be caught by the duo themselves. Nothing more came of this one night in terms of romance, but it did allow for Raj and Penny to connect with each other more meaningfully as friends from then on.

Penny and Zack

Zack and Penny in The Big Bang Theory

Of all of Penny's past bad relationships, her relationship with Zack was arguably the best and sweetest of them all. Adorably dim witted and always well intentioned, Zack was the only guy who really seemed to care about Penny and respect her as a friend in addition to a girlfriend. Of course, it was later revealed that the duo once got drunkenly married and totally forgot about it, so there were some hiccups along the way, too.

However, Zack has remained a recurring fixture in the series, appearing as recently as the twelfth and final season in order to request that Leonard serve as a donor for his and his wife's attempts to have a child -- all without really taking Penny's thoughts on the awkwardness of the matter into account.

Leonard and Stephanie

Leonard and Stephanie sitting on a couch during a date talking on TBBT

Leonard is a character who has never really been that great at sticking up for himself. He can throw out a snarky come back every now and then, and he's gotten a little better at pushing back against Sheldon whenever his onetime roommate starts to be a little too much. However, simply looking at his behavior during his relationship with Sara Rue's Stephanie -- an intimate-crazed surgical resident who was once a love interest for Howard --  shows that he doesn't stand a chance when it comes to putting his foot down in relationships.

After dating for only a few weeks, Stephanie moved herself into Leonard and Sheldon's apartment without any discussion, something that Leonard was forced to struggle with reconciling. Their breakup occurred off screen, which yet again shows Leonard's failings in terms of conflict resolution.

Raj and Nell

Raj Koothrappali and Nell in The Big Bang Theory

When The Big Bang Theory cast former 2 Broke Girls star Beth Behrs as Nell, a potential love interest for Raj, it seemed like maybe that the unlucky in love Koothrappali had met his match. Nell was a sweet school teacher who took an interest after attending one of Raj's planetarium presentations, and the two wound up spending the night together. It was only the morning after, however, that Raj learned that Nell was still legally married, although recently separated.

This more or less put an end to the relationship from the very beginning, but it was Raj's subsequent befriending of her extremely emotional husband, Oliver, and his pleading for Nell to choose who she wanted to be with, that really brought their very short lived relationship to an end.

Howard and Emily

The double date between Raj and Emily, and Howard and Bernadette

For better or worse, a lot of the guys on The Big Bang Theory have shared girlfriends in incredibly uncomfortable ways. Howard briefly dated Leonard's ex girlfriend, Leslie. Raj spent the night with Penny, Leonard's great love and eventual wife. Also, as it turns out, Howard once went on a date with Emily, Raj's serious girlfriend, that couldn't have been more of an embarrassing disaster.

Howard only realizes this fact when Raj and Emily and Howard and Berandette go on a double date together, but he promptly tells the story of how he, quite horribly, wrecked Emily's bathroom during a night together, to the point that he was forced to sneak out and never return -- an ordeal that earned him the nickname Clogzilla.

Raj and Claire

Raj doesn't always have the best first impression on women, despite his best intentions. Even years after being able to speak confidently with them without the aid of alcohol, Raj struggles to express his interest in Claire, a bartender and science fiction screenwriter, in any appropriate way. Complicating matters is poor timing for the relationship: Claire has recently reunited with a boyfriend shortly after they meet, and Raj finds himself once again ensnared by an ex-girlfriend.

Their interest in one another appears to have been genuine, despite little development, but nothing ever truly comes of it due to Raj's inability to handle being in a love triangle. Claire later appears in the series as one of his disgruntled exes, telling him that he's too needy and she found that unappealing.

Sheldon and Beverly

Sheldon Cooper and Dr Beverly Hofstadter in The Big Bang Theory

Leonard's mother, the revered psychotherapist Dr. Beverly Hofstadter as played by Christine Baranski, has always been a little bit prickly around the edges. However, the one character she has always taken a liking to is Sheldon. Feeling that he's her intellectual equal, the two have shared plenty of hilarious scenes over the years, including a scene in which they enthusiastically play Rock Band and sing "Any Way You Want It" together.

However, later in the series, after getting exceptionally drunk, Beverly surprises Sheldon with a kiss, something that thankfully only Penny witnesses. There's no telling what Leonard would have done had he witnessed it -- or what additional complexes it would have given him as part of his fraught relationship with his mother.

Penny and David

Penny flirts with Dr David Underhill in The Big Bang Theory

When Dr. David Underhill is introduced in the series, it's clear that he's going to pose significant problems for Leonard, despite being one of his scientific idols. David quickly catches Penny's eye and the two begin dating, prompting Penny to pretend to be interested in science and act entirely out of character to the way Leonard has known her to be.

Penny and David seem as if they get on well enough to work out as a couple... until, well, the final act reveals that he was married all along, and therefore a total pig. Thankfully, he was just a one episode love interest distraction, providing a means for Leonard and Penny to bond in the end.

Leonard and Mandy

Leonard Hofstadter and Mandy Chow in The Big Bang Theory

One of the dumbest mistakes The Big Bang Theory ever made was revealing a relationship that happened many, many years after it transpired. During season nine's premiere, it's revealed that Leonard once cheated on Penny while away on his research voyage with a fellow scientist named Mandy Chow. He also reveals to Penny that he still works with Mandy at Caltech to this very day, despite nearly a decade having passed since the offending incident.

It provides a source of awkward tension between the newlyweds, even more so when Mandy suddenly appears in the series for a brief stint. However, thankfully, nothing further happens between the characters -- which only further highlights the pointlessness of including this storyline at all.

Raj and Emily

Emily and Raj Koothrappali in The Big Bang Theory

Raj's relationship with Emily Sweeney, a dermatologist played by Laura Spencer, is the longest relationship he had on the series to date. After meeting through a dating website, Raj and Emily have a rocky start that involves Emily accusing him of being weird and overly passive, before later revealing just how weird and dark she is. Most of the other characters in the group wind up being afraid of her due to her many macabre tastes and quirks.

Yet, nevertheless, Emily remains a fixture on the series from season seven through season ten, though her relationship with Raj hits many, many a bump along the way. Thankfully, the series realized it wasn't a relationship that was meant to last, and Raj was able to walk away unscathed.

Howard and Jeanie

Nothing says wholesome sitcom fun like revealing that one of your characaters not only went to prom with his cousin, but also slept with them, too. Howard was originally quite a desperate character, a total womanizing pig who thought he was the best thing to ever happen to women, so it's not entirely surprising that he would have such a gross story in his past.e

However, the few details we know about his relationship -- do we even really want to call it that? -- with his cousin Jeanie are enough to make our stomachs turn. Thankfully, Howard has come a long way since then, mostly due to his marriage with Bernadette. However, the Jeanie story is still something we can never forget -- and something the series should never have pursued.

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Which couples are you glad The Big Bang Theory abandoned, and which ones do you wish they'd explored more? Let us know in the comments!