Teri Hatcher
Teri Hatcher is one of the few people on this list who actually have a slide to themselves. She was such a problem on the set of Desperate Housewives that no one had anything good to say about her. Eva Longoria noted that she was a bit of a "loner" and it came off as Hatcher having a superiority complex. Nicollette Sheridan straight out said that Hatcher was "the meanest woman in the world."
Bryan Singer vs. Rami Malek
Rami Malek reimagined Freddie Mercury in the hit movie Bohemian Rhapsody. It's not uncommon to see major actors and directors butting heads, but the relationship between Bryan Singer and Malek was intense. They often disagreed on things and got into aggressive arguments. Singer was often absent from film days which led to a lot of delays. Fox let him go.