The Big Bang Theory creator Chuck Lorre is looking back on the evolution of Kaley Cuoco’s character in the beloved sitcom’s early days.

Lorre and former Warner Bros. Television Group chairman Peter Roth joined host Jessica Radloff on the very first episode of The Official Big Bang Theory Podcast to discuss the genesis of the show, from its original unaired pilot to the Emmy-nominated hit it became.

While Cuoco didn’t appear in the original pilot, both Lorre and Roth agreed that her character, Penny, vastly improved the episode that ultimately made it to the air on CBS in September 2007, and became something of an on-screen avatar for the way they hoped audiences would feel about socially awkward scientists Leonard Hofstadter (Johnny Galecki) and Sheldon Cooper (Jim Parsons).

“They could be as obnoxious, or for Sheldon, as off-putting as possible, but you forgave them, because there was this kind of childish naivete,” Lorre said of Galecki and Parsons’ characters. “The magic of Kaley was, Kaley’s character — as we figured this thing out on the fly — was amused by them, was not critical. If she got angry, it wasn’t harsh. The audience really responded to that.”