A result of the hype surrounding the 2009 movie The Hangover.
Everybody who first paid to see it expected it to be terrible. They were all surprised by how good it was.
These people recommended it to their friends, thereby hyping it up.
Their friends went to see it, expecting it to be brilliant, only to be disappointed by how it wasn't as good as they were expecting.
= The Hangover Paradox.
Jim: Hey Bob, you wanna see a movie? How about "The Hangover"?
Bob: Sure, but it looks pretty crap.
Bob: Dude, that movie was so much better than I thought it would be!
Jim: Yeah, I'm gonna tell Jon to see it!
Jim: Jon, you've gotta see The Hangover! It's awesome!
Jon: Thanks man, I'll go see it this evening!
Jon: That was pretty disappointing. Not as good as I thought it would be.
Jim: Huh, I thought it was better than I was expecting. Guess I created The Hangover Paradox.