The Big Bang Theory was hugely successful during its entire duration on air, with fans still rewatching it episode after episode today. The show's success can be attributed to a great many factors, such as good writing, a solid premise, and of course, outstanding performances from the cast.

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While every cast member did their job stupendously, Redditor bellthebull asked their fellow fans, via a Reddit poll, which main cast member they felt had given the best performance. Redditors cast their votes and came up with results that ranked The Big Bang Theory's main cast members' performances from worst to best.

Melissa Rauch

Split image showing Bernadette angry and working in TBBT

The results of the Reddit poll put Melissa Rauch's portrayal of Burnadette at the bottom, but that is not to say that her performance was poor. Redditor MyriVerse2 pointed out that "in this case, 'worst' definitely means A-. Not a bad place to be."

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The entire cast did such a great job, and someone had to come last. However, Rauch, who was brought in well into the series, became quickly likable by audiences. Her feigned high pitched voice gave Bernadette a sweetness that hilariously contradicted her strong personality, and no one else could have played the character the same way.

Kunal Nayyar

Kunal Nayyar as Raj in The Big Bang Theory

Raj was a great example of a nerdy scientist and is one of the smartest characters in The Big Bang Theory. He is also very relatable to shy individuals who have a difficult time getting out of their shells. When Kunal Nayyar did have an opportunity to show what Raj was like when he let loose, the result was hilarious. While this happened more and more near the later part of the series, the first few seasons saw Raj unable to talk around women, which may have hindered the number of great performances Nayyar could give.

Nayyar's delivery may not have stood out against his costars, but since TBBT he has come out of his shell himself. He starred in the suspenseful crime drama Suspicion, and has received praise from fans like ChickenInASuit for "playing outside their comfort zone and nailing it."

Mayim Bialik

Amy Farrah Fowler smiling on The Big Bang Theory

Until Amy came along, no one could have guessed that there could have been anyone out there (except maybe Leonard) that could be a good fit with Sheldon. However, Mayim Bialik's character proved them wrong.

At first, Bialik portrayed Amy as practical and down to business, but as the show went on, she began to let loose, and Amy greatly matured over the duration of The Big Bang Theory. This had a positive effect on Sheldon also, whose comfort with Amy allowed him to explore other parts of his character. Because of Bialik's portrayal of Amy, fans like Sindrake felt that "Amy and Sheldon could have went on solo" after the series ended, and they would have stayed tuned to see their performances.

Kaley Cuoco

Penny looking dissappointed in The Big Bang Theory

Penny was the odd one out of the group, who also somehow managed to fit in perfectly. Kaley Cuoco's main challenge with this role was to portray a character that non-scientists and non-nerds could relate to, without it seeming as if she was being a bully to her unique friends. There was also the challenge of not making Penny appear too dumb. While she may not have understood the ins and outs of astrophysics, she was very far from being an unintelligent person.

Cuoco's performance had mixed reviews from Redditors, but many agreed that she improved as the show went on. Redditor Saltzja even stated that by the end of the series, "Kaley's [performance] was the best," and audiences became emotionally invested in her character as a result. In addition, she made Penny's relationship with the group very believable, with her friendship with Amy being a favorite to many TBBT fans.

Johnny Galecki

Leonard smiling widely in The Big Bang Theory.

Leonard is Sheldon's roommate who somehow found himself responsible for his quirky ways. Sheldon was not always an easy friend to have, and while he may have often seemed exasperated by him, Leonard cared for Sheldon greatly. With every season of The Big Bang Theory, their relationship only got better and better.

Johnny Galecki also had a challenge with his character. His reactions to Sheldon could have easily turned the audience either against him, or against Sheldon, but instead, viewers were able to care about both characters. Redditor Thewandtheywant stated that "the way he manages to express the many and strong emotions Sheldon causes in Leonard is amazing,"  going on to call him the best actor in the series.

Simon Helberg

Simon Helberg as Howard on The Big Bang Theory

Simon Helberg played Howard, an engineer who, in the beginning, tried to consider himself a ladies' man. Just like the other characters, however, he was completely clueless about the ways of women. As the show went on, Howard greatly matured but kept many of the quirky traits that made him so entertaining to watch.

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Helberg demonstrated amazing talent during his time on the show. His comedic timing and line delivery were likely the best out of the cast, and he proved himself to also be extremely skilled at impressions. Redditor Beckyd123 cited the time when the crew played Dungeons and Dragons and "he did those impersonations." Howard had the crew laughing with impressions of Nicolas Cage, Al Pacino, and even Raj. Beckyd123 described this scene as "epic."

Jim Parsons

Split image showing Sheldon playing three-dimensional chess and smiling in TBBT

Sheldon Cooper could have easily been a character that rubbed fans the wrong way. He is a genius with high opinions of himself, with various social idiosyncrasies that often left people he interacted with scratching their heads. However, Jim Parsons' portrayal made Sheldon not only lovable but extremely relatable to a community of people who often felt misunderstood.

It's hard to imagine anyone else portraying this character better than Parsons, who won a Golden Globe for Best Television Actor for this role. "I would have trouble thinking of another actor in a comedy show who displays that level of talent," said Redditor Ilmyry_maori. While every actor on The Big Bang Theory did a great job, it's hard to hold a candle to such a performance.

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