Meryl Streep and Dustin Hoffman
Meryl Streep is a notable method actor who takes her work very seriously. According to the director of Kramer vs Kramer, Dustin Hoffman was extremely critical of her acting and would often snap at her. He even made harsh comments about her past partner who passed away just to cut at her deep. She always kept her composure, but it's obvious that she's not a fan of Hoffman.
T.R. Knight and Isaiah Washington
Things got really heated behind the scenes in the early days of ER. T.R. Knight got into an argument with Patrick Dempsey. The fight was leaked to the tabloids, and in the midst of the chaos, Knight came out as gay. For some reason, Isaiah Washington decided to repeat a homophobic joke about Knight while backstage at the Golden Globe Awards. The friendship between the two was totally severed, and Washington's character was promptly written off the show.