I always tell directors not to shoot their own films, because they will slack off on the actors (I did that once) or star in it, because they'll lose an amazing amount of control.

heath

Certainly agreed on the first instance, I've had to do that a number of times on Instant Films and I always feel that my time that should be spent working with the actors is sacrificed. Can't speak to the second instance from my own experience, but obviously there have been a lot of exceptions to that one, from Woody Allen to Zach Braff...