As one of the most beloved series on television right now, This Is Us follows the lives of the extended Pearson family, spanning multiple generations and locations over nearly a century. Although much of the action of the series centers on the lives of the Big Three - Randall, Kate, and Kevin Pearson - and their parents Jack and Rebecca, side characters and relationships have been introduced that have either really resonated with viewers, or entirely turned them off.

Many of the characters in the series had already found their true loves by the time the show began, but failed relationships have been explored both in the present and in flashbacks. And sometimes, surprisingly enough, the relationships that don't get the guarantee of happily ever after have been some of the most successfully executed of them all.

This Is Us has introduced its fair share of relationships in its three season run, but not every love story is worth rooting for. Let's take a look at the best and worst of them all.

Best: Kevin and Sophie

It's not every day that someone winds up with their first, childhood love. And in the case of Kevin and Sophie, that's not entirely true, either. But from the moment a young Kevin Pearson laid eyes on Kate's best friend, Sophie, viewers were in for something truly special. In his relationship with Sophie, Kevin found something life-changing in many ways, as she revealed to him his passion for drama, and his capability of loving someone outside himself and his family.

Though the two would marry and divorce at a very young age following Jack's tragic passing, Kevin and Sophie found their way to each other again as adults. While it seemed like things may actually work out again for the onetime first loves, Kevin's addiction sadly brought their relationship to a heartbreaking end. But the series continues to explore their story through flashbacks to Kevin's teenage years, further cementing their overall significance in the story.

Worst: Miguel and Rebecca

Jon Huertas and Mandy Moore on This Is Us

It came as quite the shock at the end of This Is Us' second episode when it was revealed, in the present timeline, that Rebecca was now married to Jack's best friend, Miguel. Nearly three seasons have come and gone since that incredible cliffhanger moment, and while viewers have seen Miguel and Rebecca as a couple in the present timeline many times since, it still feels as though we know hardly anything about them.

It does the potential of their relationship a real disservice, in turn. Jack and Rebecca's relationship was built up as one of the series' true love stories, and three years in, we know almost nothing about Rebecca's second love story. The series has set the relationship up to fall short in viewers' eyes from the very beginning.

Best: William and Jesse

William Hill and Jesse in This Is Us

From the very beginning of the series, William Hill was one of the strongest characters in the entire show. As Randall's biological father, William had led a life full of considerable hardship and struggle, including a history of addiction and the loss of his love and Randall's birth mother due to their shared drug addiction.

After everything he had been through, William deserved to have some happiness before his life reached its tragic end. He found that happiness in Jesse, a fellow recovering addict with whom he bonded over music and their similar outlooks on life. In the few scenes the couple shared together, including a flashback to their first meeting in season three's Thanksgiving episode, their love story is one of the most genuine the show has produced.

Worst: Ben and Rebecca

Sam Trammell and Mandy Moore in This Is Us

Truthfully, we don't know all that much about the relationship between Ben and Rebecca. They were romantically involved when Rebecca was younger and more actively involved in the music scene, and little is known beyond that. But when the Big Three were teenagers, and Rebecca decided to give music another try, she wound up performing in bars with Ben's band, thinking nothing could go wrong.

Of course, in the world of television, getting involved in any way with an ex-boyfriend is going to cause some drama, especially when she didn't tell her husband, Jack, about her past involvement with Ben. And when Jack found out, he did admittedly act like a jealous jerk - but Ben showed his own ugly side, too, when he made an aggressive pass at Rebecca all on his own.

Best: Kate and Toby

Toby touches Kate's forehead in the hospital in This Is Us

Out of all the many couples on this list, only one can lay claim to the fact that the series has given them their own 'ship portmanteau. KaToby, otherwise known as the couple of Kate Pearson and Toby Damon, have been a fixture of the series from the very beginning. After meeting in a weight loss support group, Kate and Toby found themselves drawn to each other time and again.

Through Toby's larger than life personality and grand romantic gestures, Kate began to learn to love herself again, and feel comfortable with who she is. She opened up to love, letting Toby in little by little and revealing things to him that no one else had ever known. Soon enough, the two were married, and now, midway through season three and after a miscarriage and a recurrence of Toby's depression, they're anxiously awaiting the birth of a baby boy.

Worst: Kevin and Zoe

One of the unwritten rules of good writing is that you always want to show, and not tell. Showing two characters falling in love is always going to be more effective all around than telling your audience that two characters are falling in love. This Is Us' writing team really could have benefited from a reminder of this golden rule before it embarked on the unsuccessful third season storyline that found Kevin falling in love with Beth's cousin, Zoe.

After a brief interaction in the second season finale, the third season opened up with the reveal that Kevin and Zoe were now an item, with no natural development or progression of substantial interactions involved. The third season finds the two of them traveling to Vietnam to explore Kevin's family history, and suddenly, upon returning home, and after a sizable off-screen time jump, they're in love and moving in together. But not once has any part of their relationship felt realistic or earned - precisely because none of their development has been shown.

Best: Jack and Rebecca

This Is Us Mandy Moore and Milo Ventimiglia

Without the love story between Jack and Rebecca Pearson, there would be no This Is Us. As the central couple of the series, Jack and Rebecca have been through plenty of ups and downs, including Jack's alcoholism, Rebecca's dissatisfaction with her life as a housewife, Jack's career changes, their awful family histories, a brief separation, and much, much more.

But the couple manages to come out unscathed in the face of every obstacle thrown their way. While they may not exactly be a fairytale romance, Jack and Rebecca show time and again what it takes to maintain a happy, healthy marriage, for better or worse.

Worst: Miguel and Shelly

Miguel Jack Rebecca and Shelly in This Is Us

We haven't seen very much of Miguel and Shelly's marriage - or, honestly, all that much of Shelly's character to begin with. In their roles as Jack's and Rebecca's respective best friends, Miguel and Shelly each play an important role in the series. But when we take a closer look at the few glimpses of their relationship we've had, there's nothing good to be found.

Their eventual divorce is apparently incredibly harsh, with Miguel spending quite a lot of time at the Pearson house afterward. And seeing the way Miguel's children have been raised to resent him, and second wife Rebecca, only further reinforces the ugly nature of the one-time couple's current status.

Best: Randall and Beth

To paraphrase Randall Pearson himself, everything's better with a little R&B. Randall and Beth are one of the longest lasting couples on the series, having been together since their college days, and married not long after that. The two together are truly an unstoppable force, with endless wit and warmth and seemingly boundless support for one another.

Even in the face of difficult times - such as William's passing, Randall's anxiety attacks, Beth losing her job, and the struggle to bring Deja into the family - Randall and Beth have always been a united front. There hasn't been any obstacle too great for these two. In the absence of Jack and Rebecca's love story, Randall and Beth have become the true foundation of a new generation in the series.

Worst: Kevin and Olivia

Kevin Pearson hasn't always had the best judgment out of the Pearson clan, ranging all the way back to his impulsive years of childhood. But perhaps one of the worst choices he ever made was getting involved with Janet Montgomery's Olivia, a standoffish and conceited British actress with whom he was briefly paired on stage in his likewise brief attempt at becoming a theatre star.

The two began hating each other, but soon developed an out of nowhere attraction and relationship that just as quickly fizzled out when Kevin fell for playwright Sloane, instead. It goes without saying that when Olivia completely disappeared from the series, it was definitely a relief.

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