I think theories of humour have to explain why some jokes/stories are less funny the second time you hear them, while others remain funny forever. Does the "violation" go away after you hear the joke and your brain adapts? That seems plausible to me, but if so, why doesn't that always happen?

There's a Seinfeld episode where George gets fired -- and then decides to go back to work anyway, believing that he's teaching them a lesson. I've seen it many times, so I know exactly what's coming, but my brain still can't seem to prepare itself for the deep, character-consistent idiocy of it. I will never not laugh while watching this. The question is: Why?