Shannen Doherty
90210 sweetheart Shannen Doherty wasn't exactly the nice girl while the cameras were off. She was accused of being incredibly difficult to work with, constantly late, and starting fights with her coworkers. That's the definition of diva behavior, and likely why her career after the show was pretty sparse.
A Long Battle With Cancer
Despite her shadowed past with Hollywood, Doherty is still liked among her former castmates. She is also relatively private and only disclosed late in her battle with cancer that she was sick with breast cancer. However, she did beat it, and when co-star Luke Perry died, she shared one of the most heartbreaking tributes among the 90210 cast.