According to Patty Lin, a former staffer, the actors of the hit sitcom Friends were not always supportive of the show’s writers. In her new book, Lin reveals that Jennifer Aniston, Lisa Kudrow, Courteney Cox, Matt LeBlanc, Matthew Perry, and David Schwimmer would intentionally sabotage jokes they didn’t like, forcing the writers to come up with alternative versions.

Lin worked on the seventh season of Friends, joining the writing staff late in the series’ run. She describes her initial excitement about being in the same room as the cast but soon realized that the actors seemed unhappy and constantly concerned about how each script would serve them.

Lin writes that the actors knew how to get a laugh, but if they disliked a joke, they would deliberately tank it, leading the writers to rewrite the scene.

The actors would also voice their opinions during rehearsals, often arguing that their characters would never say or do certain things. Lin states that these sessions were aggressive and lacked the levity one would expect from a sitcom. Lin’s book, which explores her 10 years of scriptwriting and her decision to leave the industry, will be released on August 29.