Pat's got potential, he really does, but he falls victim to being type-casted, and I think a lot of it has to do with Puddy from SEINFELD, since that was pretty much the role that really launched his career... though interestingly, Puddy's pretty much a completely different character in his debut episode: he's a decent, hard-working mechanic, who can actually speak coherently, as opposed to that mumbling, squinting, clueless oaf he became known for.
Then again, Jonah Hill has a similar problem. He actually wants more work in serious movies, like that MONEY BALL he did with Brad Pitt, but he keeps getting typecasted in these lowbrow comedy movies.