After 12 seasons of 'The Big Bang Theory' it is very clear, we won't see another character on television close to Sheldon Cooper, aka Jim Parsons. Given his talent across the board, his decision to leave the show was a tough one to digest for both the fans and the cast on the show. The likes of Kaley Cuoco saw the series going on at least another few years, however, she was shocked to find out that Parsons wasn't feeling the same way.

As Parson revealed with The Hollywood Reporter, there was no specific moment that swayed his decision, he just felt as though the time was right, "There was no factor; there was no situation that I was like, 'Well, I've had enough of that.

' No. There was nothing like that. It was just…when you know, you know. 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," Parsons continued. "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. "

We saw some incredible moments on the show - though some, Parsons might want to forget about. As he discussed in a prior interview, he wasn't all that comfortable with a certain episode that sprung some of his allergies.

Sheldon And The Cats

Just imagine being allergic to something and having to be surrounded by that during an entire episode. That's exactly what happened with Parsons, who was asked prior to the shoot of the episode if he was allergic to cats. Although he said yes, they still went on with the episode, giving the actor a box of Claritin.

The pro that he is, Sheldon went on with it, though as stated by Cinema Blend, it was quite the experience given that it was multiple scenes, "There was one time very early on in Big Bang where they were tossing around an idea for a script and they came up and asked me, 'Are you allergic to cats by any chance?' And I said, 'Yeah I am, my eyes get puffy and whatever.' About a week later, the script showed up with a box of Claritin, and it was like, 'Here, we're going to do one where you're surrounded by cats the whole episode. I have gone through that… but I was fine, I just didn't touch my face."

Luckily for Parsons, he survived the episode without an allergic outbreak. He must've been livid on the inside!

Sources: Cinema Blend & The Hollywood Reporter