M. Night Shyamalan
M. Night Shyamalan seems intent on proving there's no job in the film industry he can't handle. Unfortunately, when you become an overnight moviemaking sensation (which is exactly what The Sixth Sense turned this writer-director into), few people are going to be brave enough to tell you "no." But studio heads should have shouted a vehement "hell no!" against Shyamalan's repeated attempts to cast himself in his own films.
While his characters never logged much screen time—which is fortunate, as he is painful to watch on-screen, especially when acting alongside actual talents like Paul Giamatti—he hasn't done much to help his reputation as a megalomaniac by casting himself in his films' most powerful roles. In the unbearable Lady in the Water, for example, he plays Vick Ran, an author whose ideas are so brilliant, they will change the course of humanity for the better. Umm, really?