Originally Richard Gere was cast into one of the four lead roles for the 1974 film, The Lords of Flatbush. During filming he and Sylvester Stallone got into a fight which turned into a shoving match. Consequently, Stallone refused to work with him and Gere was fired. What was the fight over?
Apparently what happened is that Gere got too into character during the filming and repeatedly irritated Stallone. This came to a head when Gere, carrying a sandwich, got into a crowded car with Stallone despite Stallone's objections. Gere then proceeded to spill mustard out of the sandwich onto Stallone while eating and that was it for Stallone. He elbowed Gere out of the car and made an ultimatum to the director which resulted in Gere being fired.