The relationships on The Big Bang Theory are what made this show so great. Through ups and downs, breakups and makeups, promotions and failures, this gang came out on top together. Thanks to Leonard moving in with Sheldon years ago, Sheldon not only gained a best buddy and a furnished apartment but he gained two new friends with Raj and Howard. However, no one gets under Howard's skin quite like Sheldon.

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Among the four men, Howard is the only one without a doctorate, which Sheldon brings up time and time again. Due to their differences in degrees and general lifestyle, these two tend to butt heads more than the rest of the group. Sheldon respects Raj's intelligence and degree and calls Leonard his best friend. But Howard? He's just a "treasured acquaintance." Let's take a look at 10 times these two were anything but friends.

SHELDON REFUSES TO ACKNOWLEDGE HOWARD'S DEGREE

Leonard, Raj, Howard, and Sheldon have lunch at Caltech in The Big Bang Theory

As aforementioned, Howard is the only one without a doctorate. However, that does not mean he's uneducated and doesn't fit in with this group. He has a master's degree from MIT and has been to Outer Space for crying out loud.

He's a professional in his chosen field of engineering and is good at what he does (you know, when he's not crashing the Mars Rover to gain female attention). But Sheldon looks down on Howard and his education and doesn't think he's bright enough. True friends don't judge one another on their education.

HOWARD CROSSED BOUNDARIES BY HITTING ON SHELDON'S SISTER

Before Howard fell in love with Bernadette and got married, he was a true horn-dog. He would chase after any woman that looked in his general direction. And when Sheldon's beautiful twin sister, Missy, came to town, his demeanor didn't change.

He tried hitting on her multiple times and then fought with the group about who was going to date her (even though they never once thought about what she wanted). Once Leonard told Sheldon about Howard (and Raj's) plan to woo Missy, Sheldon was incredibly disturbed. Sorry, Howard, but friends don't sleep with friends' siblings.

SHELDON CALLS HOWARD AN AQUAINTENCE

When Sheldon decides to move from Pasadena, he leaves a goodbye video for his friends because he's not good with goodbyes and general emotion. In the video, he explained that he's leaving behind four friends and a "treasured acquaintance."

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They all assumed Penny was the acquaintance due to their educational differences but as it turns out, Howard was the treasured acquaintance. Choosing Penny over a man he's known and worked with for years? That just proves that Sheldon's been tolerating Howard.

HOWARD RETALIATES BY BEING A BAD STUDENT IN SHELDON'S CLASS

Sheldon hit a dead end researching and studying string theory. After years of dedication and passion, he finally realizes it's time to move on. He decides to focus on dark matter, the only problem is the grant that's paying Sheldon's salary is for string theory. The way around this confusion is to let Sheldon become a junior professor at Caltech so he can study whatever he chooses.

The only problem is no one signed up for his class. Seeing this class as a potential stepping stone to his doctorate, Howard takes the class. Sheldon, of course, doesn't think Howard is smart enough to take his class and treats him poorly, which results in Howard being a poor student and taunting him. In this scenario, both were in the wrong and it's not something real friends do.

SHELDON FELT ZERO REMORSE ABOUT READING A LETTER FROM HOWARD'S DAD

In Sheldon's defense, he doesn't pick up on social cues and doesn't have the emotions that us "non-genius" folk have. However, as a person who grew up with a dead-beat father and later laid his father to rest, Sheldon should be very familiar with the pains of growing up without a dad.

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It wasn't easy for Sheldon and relied on his grandparents and mother. So, when he found a written letter to Howard from Howard's father and read it, he crossed many boundaries. Howard was horrified by Sheldon's actions, mainly because he never even read the letter himself. Sheldon's a genius but he missed the mark on this one.

HOWARD MAKES FUN OF SHELDON'S IDIOSYNCRASIES ON HALLOWEEN

TBBT Friendships Sheldon and Howard

While it was hilarious when Howard dressed up as Sheldon for Halloween, it was also quite hurtful. As Sheldon's "acquaintance," he should know that Sheldon doesn't pick up on sarcasm very well and doesn't like being made fun of (who would?). Howard didn't just dress as Sheldon, he acted like him, too.

He chose all of Sheldon's silly quirks and brought them to life in a robotic formation. Sheldon didn't even realize Howard was making fun of him until later, which was heartbreaking. And yes, Sheldon later dressed as Howard as well but only because Howard started it.

SHELDON TRULY BELIEVES HOWARD DOESN'T KNOW PHYSICS

Sheldon wearing a beige jacket sitting next to Howard who is holding a margherita

As a trained engineer, Howard is very intelligent in all subjects. Let's just say he knows a little about a lot of things. He's obviously good at what he does because he had the chance to work with Stephen Hawking, which made Sheldon incredibly jealous. And when Sheldon began teaching, the two went back and forth on who was smarter.

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Sheldon even reported Howard to human resources for his behavior (again, not something friends do). "I told you you weren't smart enough," Sheldon blurted out at Howard. Perhaps if these two put their egos aside they could actually be authentic friends.

HOWARD DIDN'T WANT TO GO INTO BUSINESS WITH SHELDON

In "The Application Deterioration," we see Sheldon, Howard, and Leonard patten an idea that could help the university. Once the group found out that the university would own most of their idea, they decided to do it themselves and divide the share three ways.

This would have worked out well until Bernadette reminded Howard of what a horrible friend Sheldon was and how he'd probably screw him over. She asks if a lawyer could look over the contract before signing anything because, at the end of the day, these two really didn't t trust Sheldon.

SHELDON REFUSES TO GIVE UP HIS PARKING SPOT

Sheldon Cooper's parking spot in The Big Bang Theory

Sheldon hates driving and refuses to do it. We've only seen him drive a few times and they were in emergency situations. He has Leonard drive him to the university every morning and when he begins dating Amy, he uses her for his transportation needs as well. Since he doesn't own a car and doesn't drive, his given parking space at the university was given to Howard.

This greatly upset Sheldon because that was "his" spot. Sheldon made it very difficult for Howard to park there — even moving his office outdoors so Howard had no choice but to park somewhere else. And when Howard finally did get in the spot, Sheldon hopped in Howard's car and sat in his seats naked!

THE ONLY REASON THE TWO STAY FRIENDS IS BECAUSE OF LEONARD

A throwback shot of Leonard and Howard playing video games on TBBT

Let's be honest, if weren't for Leonard, Howard and Sheldon would not be friends. They may have said hi to each other in the cafeteria but that would be it. They're both in two different fields of study and behave entirely differently. To be honest, Howard would probably be siding with Leslie Winkle and Barry Kripke for their disdain over Sheldon Cooper.

Back in the third season, we learned that Leonard met Howard and Raj at the university and brought them to meet Sheldon, where the four finally became a clique. Howard and Sheldon may tolerate and have a soft spot for each other sometimes, but they're not true friends.

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