The rule of thumb for a director or producer - which prevents them from just sticking their names on everything - is that you have to contribute substantially more than 50 percent of the character dialogue and story.
Harold RamisA psychologist said to me, there are only two important questions you have to ask yourself. What do you really feel? And, what do you really want? If you can answer those two, you probably can leave your neuroses behind you.
Harold RamisThe comic impulse is sometimes a reaction to sadness. You feel like you can make one choice or the other.
Harold Ramis