Well I can't say what, but let's just say most of the things that happen here - so no pun intended. I am a sucker for movies like this one. "Funny" (it's a movie so do not get offended, I would not like to see anything like this happen in real life ... to anyone) and really cleverly written. Twisted and depraved at times (no prisoners taken) and probably unrealistic ... health wise that is) ... but filled with tension and edge of your seat stuff.
The movie is really something ... well I'd say special. If you like convenient things happening quite often - also there are flaws when it comes to logic or how stuff can happen (like leaving a building without anyone noticing, at the beginning of the movie, just try not to think about it ... at all) ... but the movie needs you to suspend your disbelief!