Alec Baldwin and Shia LaBeouf
While working together on the broadway play, Orphans, Baldwin was attacked by LaBeouf for not memorizing the lines. In the events that followed, Baldwin asked the production to let him quit. They instead chose to fire LaBeouf.
I wouldn't work with either of them. I don't much like being punched. ...or shot.
Snipes spent almost the whole time in his trailer getting stoned, barely showing up when needed, and at one point attacked the director trying to kill him.
Snipes basically left the production, half of his scenes unshot, leaving the rest to try to cobble together a movie with half rewrites and workaround scenes to make it a somewhat coherent movie.
It was the whole reason why the movie was so bad.
He refused to memorize his lines, and often couldn't even say them because of how baked he was. There's even a scene where, just to be a d@#k, he refused to open his eyes. They had to CGI the eyes in after.