My job is to come up with something that you like and you agree with that you would play wholeheartedly. If we disagree, I may not be doing my job correctly.
The first comedy screenplay that I wrote was Animal House and I always thought I could and should be a director but no one was about to give me that opportunity on Animal House.
With both Caddyshack and Vacation, it's not like the subjects were serious enough that they engaged my interest for another round. I love the characters, and the actors were great, but I didn't see the need to make another Vacation movie.