Julia Roberts and Nick Nolte
These two hated each other so much that they could barely film I Love Trouble together. Oftentimes, the actors used body doubles in scenes where it didn't matter if their face was showing or not. In fact, they barely spent any time together on set due to how much they despised one another.
Roberts and Nolte both went their separate ways after filming wrapped, but that didn't mean their feud was done and over with. In fact, Roberts prodded the fire by saying that Nolte could be "charming and nice, he's also completely disgusting." Nolte ended up saying that no nice person would call another disgusting, "but she's not a nice person. Everyone knows that."