The recent spat between two actors on Grey's Anatomy attests to this fact. It goes on to report:
It turns out there was even conflict on "I Love Lucy," where the cast seemed to be getting along so well. But it was not the case.
"Going back to the 50's, there were reports that Lucille Ball made Vivian Vance wear dresses that were two sizes too small to make her look frumpy by comparison. Vance was also very dissatisfied with her co-star, her husband played William Frawley, who was 22 years her senior. She felt very insulted by the fact that she was playing the wife of a man in her words "that was old enough to be her father.