You can work on a movie for years, and you won't know until you show it to an audience for the first time if it makes any sense to them at all, if they're touched, if they find it funny, so it's endlessly exciting, because failure is just right there all the time, and your chances of success don't rise that much based on the fact that you succeeded last time.
Judd ApatowI think, there were probably problems with show business where producers and directors would try to get the writing credit also. So they created a rule where the bar, to get your name added to the writing credits, if you've done a revision, is very high if you're also the producer or director.
Judd ApatowEvery joke is an experiment. When you sit, alone, and write a script, or just a joke, you really have no idea if it will succeed.
Judd Apatow