Johnny Galecki has revealed his favorite episodes of the beloved sitcom The Big Bang Theory. Chuck Lorre and Bill Prady's brainy television series had a critically successful 12 season run, clocking in a whopping 279 episodes. The show follows five nerdy co-workers living and working in Pasadena, California. Galecki plays one of the leads in the ensemble cast, Leonard Hofstadter. Leonard falls in love with an aspiring actress across the hall named Penny (Kaley Cuoco), and the series chronicles the ups and downs of their relationship.

The delightfully comedic cast is one of the biggest highlights of the show. Jim Parsons' performance as the neurotic Sheldon Cooper is so popular that it produced a successful spinoff series, Young Sheldon. Johnny Galecki brings a vulnerable realism to physicist Leonard Hofstadter, making the awkward man wholly relatable. The Big Bang Theory also benefits from its callbacks to previous episodes and its hilariously involved plotlines. The sitcom has a lot of science and a lot of heart.

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In an interview (via TBS), Johnny Galecki lists five different episodes as his all-time favorites. Much of his reasoning behind the choices have to do with Leonard's character growth, his relationship with Penny, and some of the actors he got to work with during the show's 12 season run. So, without further ado, here are Johnny Galecki's favorite episodes of The Big Bang Theory.

Season 3, Episode 19, "The Wheaton Recurrence"

Wil Wheaton pointing at Sheldon's forehead

The first episode Galecki cites is "The Wheaton Recurrence." In this one, Leonard tells Penny he loves her for the first time, and her response is less than ideal. Outside of Wil Wheaton's humorous run on the show, Galecki says he enjoys the episode because "It was the very personal moments, such as the character having his heartbroken, that permitted us to mature him. That was always exciting as I knew it would be a changed Leonard moving forward. Still Leonard, but that I’d need to consider that he would see things differently."

Season 4, Episode 15, "The Benefactor Factor"

Jessica Walter in The Big Bang Theory The Benefactor Factor

The next episode Galecki mentions as a Big Bang Theory favorite is "The Benefactor Factor." The season 4 installment has Leonard questioning whether or not he'd be willing to sleep with an older woman in exchange for a donation to Caltech. Why does he like this episode? Galecki mentions working with Jessica Walter, who plays Mrs. Latham, the wealthy benefactor, as the main reason. Penny also gets to see a side of Leonard she might not have thought about.

Season 6, Episode 8, "The 43 Peculiarity"

Kaley Cuoco and Johnny Galecki in The Big Bang Theory The 43 Peculiarity

"The 43 Peculiarity" also makes Galecki's list because it has to do with Leonard's character growth. Leonard becomes jealous of Penny's new study partner, and in a heated argument, she admits her love for him. While the TBS article mixes up Galecki's quotes, the reasoning behind his choosing is the environment of the taping. Penny and Leonard's fight and her admittance of love are filmed all in one take. Galecki states, "This was probably my favorite memory of a live audience taping. It felt very private. The cameras, crew and audience kind of disappeared in that moment. And that was the moment we used."

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Season 7, Episode 3, "The Gorilla Dissolution"

Penny and Leonard in The Big Bang Theory

The actor feels that "The Gorilla Dissolution" shows a new side of Leonard Hofstadter. The penultimate episode features a major step in their relationship when Penny and Leonard get engaged. "The Gorilla Dissolution" had a viewership of 14.4 million people, making the episode one of the highest rated in the series. Galecki says, "I found it heartbreakingly sweet Leonard quietly carried a ring for God-knows-how-long. For all of his math and science, Leonard was a diehard romantic sentimentalist." 

Season 8, Episode 22, "The Graduation Transmission"

Kaley Cuoco and Johnny Galecki in The Big Bang Theory The Graduation Transmission

The final episode on Galecki's list is The Big Bang Theory season 8, episode 22, "The Graduation Transmission." Leonard is supposed to deliver a commencement speech at his old high school but faces trouble when bad weather affects his plans. He eventually makes it to the graduation and decides to change his speech for the better.

For the most part, Johnny Galecki likes episodes that highlight Leonard's growth and focus on his relationship with Penny. Since The Big Bang Theorythe actor returns to his roots by appearing briefly in the Rosanne spinoff, The Conners. With The Big Bang Theory being such a critical success, there's no doubt that the actor has a bright future ahead of him.

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