I'd heard this movie was horrible. Boring. Dumb. Pointless.
I watched it a while back and realized pretty quickly that the people who say that about the movie can usually be described by at least two of the words I just used.
You can't watch that movie thinking you're going to be watching some formulaic horror movie. It's really a movie that you can't label. The first part of the movie is sort of slow, but sublte. About the time you're going to turn it off, you realize something is about to happen that you need to see. Abruptly it segues into the second part of the movie (it is actually broken up into three parts) and suddenly you're thrust into this lightening-fast WTF-inducing very dark, very twisted whose-line-is-it-type black comedy situation. You don't know who's crazy. You don't know if anyone actually is or if its just human nature. The social commentary during this point is spot-on and occasionally cuts pretty deep. And it's really funny. Some great one-liners and obvious-answer type stuff.
The third part is like turning a sharp right after going straight at 100 miles an hour. You've suddenly got emotions and a twist that I really didn't 100% grasp, although I understand what on a basic level (if that makes sense LOL). The characters, some of which have been really shallow and 2-D show some depth and development.
Definitely a movie to see--if you're not going to take it too seriously and can think outside the modern Hollywood box!