It's well known that Jerry Seinfeld has turned down offers to host the Oscar ceremony in the past. But why?

Recently, he blabbed to Britain's Empire magazine, "If I hosted the Oscars and I did it really well, they would just ask me to do it again. And then again. And again. There's no up-side. I don't know, it's just a weird environment. I'm lucky that I can do things that kind of interest me as a challenge, but everybody there is nervous, you know? They want to win their award. They're not there to have fun. I like to go in front of an audience that wants to have fun."