Friends

The episode where Phoebe thinks her dead mother has been reincarnated as a cat was written by Marta Kauffman at the time when her own mother recently passed away (the episode was dedicated to her). In an interview with one of the other writers, they admitted that said this would have gotten shot down at the table read, but nobody felt comfortable saying "no" under the circumstances.

The original idea for the show was going to focus on four characters with Phoebe and Chandler in supporting roles. In the early stages the creators toyed with the idea of Chandler being gay. They changed their mind when they met Matthew Perry. They did, however, insert many jokes about Chandler having gay mannerisms (not knowing about sports, loving show tunes, etc.).

Lisa Kudrow was terrified of the duck that showed up in Season 3.