3. Sylvester Stallone and Richard Gere
Stallone and Gere were supposed to act together in the Lords of Flatbush, a 1974 movie. The two didn’t get along well. At the time, there were rumors in the tabloid press about how Gere liked a certain paraphilia involving a gerbil up his behind. Gere believed that Stallone started the stubborn rumor. The two got into a fistfight, the conclusion of which was that Gere threw chicken grease on Stallone. He was fired as a result. The two hate each other so much that they have refused to work together ever since.