I am the kind of person who will laugh my *ss off at anything from a dumb sitcom to, well, a smart sitcom. That said, I have read several PS's where I found the writer's sense of "humor" absolutely, positively not funny. And in one case, politically incorrect enough (jokes about AIDS orphans in Africa, ha ha!) to get his whole application thrown in the trash. Make sure to have a broad range of people read your PS and tell you if it's actually funny.