Film and TV classics such as “I Love Lucy” and “Dirty Dancing” are filled with some great on-screen chemistry between the actors. But because of their talents, sometimes you assume that these people get along when the camera stops rolling too, even when this isn’t always the case. This new article from The Huffington Post features some surprising revelations about tension behind-the-scenes that we’d have NEVER picked up on otherwise. I mean who would have suspected that Jennifer Grey and Patrick Swayze sometimes sparred in between takes? Check out the rest of the list here.