The Big Bang Theory is ending after 12 seasons and 279 episodes because Jim Parsons realized he didn't want to do it anymore, and the producers decided they'd rather end the show than keep going without a member of the ensemble. ("I couldn't wrap my head around the idea of going on without the whole ensemble — and the whole ensemble is why we succeeded," co-creator Chuck Lorre said.) Negotiations for a 13th season were starting to happen last summer when Parsons made his decision, and the four-time Emmy winner opened up to The Hollywood Reporter about his thought process in making that call. According to Parsons, the choice to say goodbye to Sheldon Cooper was a pretty intuitive one.

"It was the first time in my life of doing this show that it occurred to me that I might want to not do another contract after [season] 12 was up," Parsons said. "I don't know if it's because I'm an Aries or just because maybe I'm in touch with myself. Whatever it is, once I had that thought, I was like, 'Well, that's your answer.'" Pretty un-Sheldon-like thought process, if you ask us.

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He said that there was nothing that made him unhappy or sick of doing the show. "It was just ... when you know, you know," he said. "And you're susceptible and thrown around by the whims of your own existence and getting to a certain age and your life changes and suddenly you just think different. It has been fascinating to think about who I was 12 years ago. And sometimes when I have trouble learning a line or saying a line of Sheldon's right now, it's hard to know why specifically. But it's like, you're not the same person you were. There is a possibility that this actually became more difficult for you in a way. And I don't know what that means but it's like you just change."

Parsons has been busy with non-TBBT projects like performing in The Boys in the Band on Broadway, producing shows like Netflix's Special, and acting in the movie Extremely Wicked, Shockingly Evil and Vile. So the end of The Big Bang Theory gives him more time to pursue other passion projects like these. Plus he'll still lend his name as an executive producer and his voice to the spin-off Young Sheldon.

The Big Bang Theory series finale airs Thursday, May 16 at 8/7c on CBS.

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Jim Parsons and Mayim Bialik, <em>The Big Bang Theory</em>Jim Parsons and Mayim Bialik, The Big Bang Theory