Why does America laugh at "FAIL?"

FAIL is an internet sensation!  But why?  From websites that specialize in showcasing intellectual blunders to general comedy sites chock-full of "fails," it's clear that American web users, (as well as the wider English-speaking internet), enjoy viewing, commenting on, and laughing at other people's mistakes.  In fact, many of these photoblogs are user generated; all pictures are uploaded (and captioned where applicable) by fans.  And considering the sheer volume of images and web hits, that's a lot of fans.  But why are these pictures so popular?

An Average Sample:

FAIL offers three cheers for epic stupidity, from momentary lapses in judgment, immortalized on film, to remarkable alternatives for critical thinking.  American culture appreciates instant irony, which is often embodied in FAIL pictures.  There is also a sense of relate-ability that lets viewers poke fun at themselves, (who hasn't left the lens cap on at some point?), yet also makes them feel subtly more intelligent, since they can easily identify the problem and don't envision themselves, say, hosing down a car in the rain.  It's also something of a puzzle.  Everyone has ideas that sound brilliant at the time... And there's an amusing challenge in the question "what were they thinking?"

Personally, I laugh at the irony: how people can do the perfect opposite of what makes most sense.  But whatever the appeal, FAIL pictures remain part of American cultural humor.