10 Insane Rules The Big Bang Theory Cast Had To Follow

Because the cast's palpable banter, spot-on delivery, and memorable zingers, you'd assume a lot of show's best one-liners were ad-libbed. But while Melissa Rauch (Bernadette) was interviewed by Huffington Post, she explained how her fellow cast members have little incentive to deviate from their lines because of the tight script. In her own words, "I love it so much, but you don't want to mess with what they write because it's almost like this beautiful concerto that you don't want to mess up one note of."

Although the actors are expected to follow the script, some improvised moments proved too funny to cut. Amy's outrageous reaction to her tiara, Bernadette's squeaky voice, and Amy's spanking scene were made up on the fly by the actors. Even though Stuart was meant to be an ordinary bit part, Kevin Sussman changed everything when he improvised the line, "I love you" to Penny. The audience loved his delivery so much, Stuart persona was tweaked to be more troubled and pathetic, and the character was made a regular.

Because of how well moments like this turned out, it's a relief the actors didn't stick to their lines verbatim.