I recently read a poll in England where the readers voted 'Vanilla Sky' as the most confusing film they've seen. I can't understand why. The entirety of the plot is told to the viewer at the end. Maybe people were expecting a rom-com when they purchased their tickets and not a sci-fi piece about the reality we choose. Most I know don't care for this film, but I like it. I will admit the film it was based on (i.e. ripped off) was far superior.
I'll chronicle the films I found myself trying to wrap my brain around when the credits rolled. Feel free to add your own in the comments as I'm sure I'll be missing something.
1. 2001 - A Space Oddessy: While the first two acts are simple enough to follow and the symbolism isn't difficult to grasp the ending of the third act is a bit of a mind twist to say the least. While it didn't require much thought to grasp the concept of the monolith I've given up trying to figure out what was going on exactly in the room sequence.
2. Memento: You may be saying this wasn't confusing at all even with the non-linear story line, but there's one quick shot that throws me. You know what I'm talking about. Still it's one of my favorite films of all time and I highly recommend it.3. Primer: It helps that I don't have a strong background in physics, but I never truly understood what was going on in this story of time travel gone completely awry. I've been told that repeated viewings help, but the aesthetics of the movie hardly warrant it. Still it's an interesting tale, if not cheaply constructed.4. Lost Highway: I think David Lynch loves messing with his fans. Oh and he likes drugs. Lots and lots of drugs. I watched this film with my friend Corey who's only comment after the credits rolled was a raise of his hands and a baffled look. Actually it's unfair to pick on Lost Highway alone as a lot of Lynch films (Eraserhead, Mullholland Drive) would qualify. Still I enjoyed this for reasons I can't explain.5. Zardoz: I can't recommend this film at all unless you really like weird, B sci-fi films that make little sense. In the first five minutes there's a floating stone head that rants about how the penis is evil and the gun is good and orders a bunch of hairy men in skimpy outfits to take up arms and kill. It then spews a bunch of weapons and ammunition out of it's mouth. It gets stranger after that. When Sean Connery in a wedding dress is the least surreal aspect of the film you know it has problems. Still considered a cult classic by many, but one I'll never even attempt to watch again. The most confusing aspect of this movie is trying to figure out how it ever became one.
"Every once in a while, a movie like that comes along; a movie you've got to see so that you, too, can be in the dark about it. In the movie's (Zardoz's) own terms, this much can be said for sure: It may not make you an Apathetic, but it will certainly age you by two hours." - Roger Ebert