Oooh, what does it all mean?

I have to say that the ending to this film was one of the most abrupt and stupidest of any that I can recall. I know an ending like this can conjure up theories based on some deep meaning, but if you ask me, there wasn't much developed in the plot for there to be fodder for an ending that was interesting and that made some sense, so they threw this bizarre bit at us - and probably with the hopes that we're all going to be going "Oh, what does it mean?" and developing and discussing all these theories to explain it. Coming up with a decent and coherent ending is a common problem that is apparent if you watch a lot of films, and I've had the same suspicions as I do about this one a number of times. This one just seemed to be more blatant.