The Big Bang Theory ran for twelve seasons, and it followed four scientist friends as they grew up and learned all kinds of life lessons in the heart of Pasadena, California. Many fans agree that Dr. Sheldon Cooper is the heart of the show, thanks to an incredible acting performance by Jim Parsons, and many plot threads somehow involve him, one way or another.
Fans have plenty to like about Sheldon, from his passion for his work to his blossoming relationship with Dr. Amy Fowler and his whimsical imagination. But there is also a lot to not like about him, and the other characters comment on this in practically every episode. Sheldon has a reputation for many quirky or negative character traits, and they all hold him back as a person. What are they?
10 Sheldon Has Killjoy Tendencies
The main characters of The Big Bang Theory have all kinds of fun, from comic book debates to LARPing The Lord of the Rings characters and online video games, and they all try to be sporting about it. Sometimes, though, Sheldon can't help himself and dampens the fun one way or another.
Sheldon is quick to correct other people or focus on the little things, and he often brings a group activity to a halt with his corrections and nitpicks, which no one appreciates. He ought to let these things go so the activity can proceed smoothly.
9 Sheldon Is Often A Smarty-Pants
Many of Sheldon Cooper's worst personality traits are connected or feed off of one another, and one of his most all-encompassing negative traits is his smarty-pants attitude. Sheldon is certainly well-educated, having two Ph.D.'s and a Master's degree, but there is no need to keep flaunting his immense knowledge.
It's one thing to inspire others with trivia and cool facts, but Sheldon takes this to a negative extreme and annoys everyone with his pathological need to be the smartest person in the room. Not every fact or trivia bit needs to be shared.
8 Sheldon Is Highly Competitive
Sheldon is quick to compete with others and accept any challenge he deems worthy, though this does not always end well. It's good to have some competitive spirit, but Sheldon, being himself, usually takes this to an awkward and excessive extreme.
For example, Sheldon often competes with fellow physicist Barry Kripke, and they have an amusing but rather dysfunctional rivalry. Sheldon also gets highly competitive in online gaming and won't accept failure under any circumstances. Nor can he stand to lose an argument.
7 Sheldon Is Vengeful If He Loses
Similar to Sheldon's competitive side is his vengeful side, which often arises after he loses a competition or loses face to someone else, often Barry Kripke. Sheldon has a few ongoing feuds with co-workers and other assorted parties, and anytime someone one-ups him, he feels the need to strike back to get the final word.
Sheldon was scared witless when Raj, Leonard and Howard thoroughly pranked him near Halloween on campus, so Sheldon got Leonard back with a terrifying zombie prank right there in their living room. He also got back at Barry with a foam prank in Barry's office.
6 Sheldon Can Be Extremely Blunt
It's one thing to be a "straight shooter" and stick to the facts, but there is such a thing as tact, and Sheldon often lacks it. His tactless side leads him to be horribly blunt to even his friends and family, and he won't think twice about making a harsh observation about someone out loud.
In fact, Sheldon isn't even always aware that he is crossing certain lines with his bluntness. Sometimes, he does it as criticism, but other times, he is merely stating his mind with too few filters, and someone usually gets upset by his blunt-force statements and observations, often Penny or Leonard.
5 Sheldon Has A Tendency To Be Argumentative
Similar to Sheldon's competitive streak is his tendency to get into arguments, and he is often the one to initiate these verbal exchanges. Sheldon isn't the type to let any snide remark or inaccurate statement slide, and he is quick to respond with a correction or heated retort.
Sheldon ends up wasting a lot of time getting wrapped up in petty or unconstructive arguments, and he won't back down until the other party can actually prove him right, or if Sheldon finds something even more interesting to think about. He only very reluctantly concedes the cricket argument with Howard in Season 3, for example.
4 Sheldon Is Rather Inflexible
Overall, Sheldon can be described as a stubborn person, and he is also inflexible to the point of making any endeavor hopelessly complicated because he can't stand to have his routines disrupted. Even going to a movie theater is tough because Sheldon won't bend his demands.
Habits and routines can make a life comfortably stable, but Sheldon takes this to a ludicrous extreme, often complaining or panicking if anything deviates from his rigidly-defined norms. Sheldon is missing out on a lot because he likes to set every aspect of his life in stone.
3 Sheldon Makes Everything About Himself
One of Sheldon's most distinct and disliked personality traits is how incredibly self-absorbed he can be, in terms of his career, his hobbies and practically anything else. Sometimes, Sheldon will take an interest in someone else's affairs, but in his mind, everything should be connected to him somehow.
Even when Leonard is having girl problems, Sheldon will try to steer the conversation back to his own (unrelated) problems, or he will inconvenience everyone while trying to get everything done his own way. His self-absorbed streak often manifests as his self-serving inflexibility, such as when the friends are planning a trip to the movie theater or a restaurant. It's all about Sheldon, evidently.
2 Sheldon Is Conceited To The Point Of Arrogance
Practically every other The Big Bang Theory character agrees that Sheldon Cooper has a rather big head, which stems from his genuine brilliance and his self-absorbed nature. Sheldon goes way beyond self-confidence; he is prideful to the point of alienating everyone around him.
Sheldon is convinced that he is the smartest, most important and most respectable person on the planet, and while there is some merit to this, Sheldon gets carried away and sabotages himself with his sheer arrogance. When he made a breakthrough in his research, for example, he paraded around the room chanting "Sheldon and his brain!" over and over. Now that's conceited.
1 Sheldon Has No Respect For Boundaries
This aspect of Sheldon's personality was mainly explored in earlier seasons, especially in the first five episodes. Sheldon's most worrisome attribute is his total lack of boundaries, and he will say or do anything if he thinks it's right, regardless of what other people or even the law have to say about it.
One of Sheldon's first acts was to actually sneak into Penny's apartment at night to compulsively tidy up the place, and even leave a note with suggestions. He's lucky he didn't get the police called on him for that. And that wasn't the only time he annoyed Penny by waltzing into her apartment to settle an issue or talk things out. He also has restraining orders from a variety of real-life celebrities the show mentions, such as Bill Gates and Carl Sagan.