Am I the only one who gets annoyed when people think inception was some stupid-deep, hard-to-understand movie? It was (I thought) very straight-forward. The bigger problems with the movie come from the plot holes pointed out by Pewpewarrows. Do those holes perhaps contribute to the confusion?
At first watch it's clear (apart from the ending sequence) what parts of the movie are dreams and what parts are reality, but when you watch it again you may start to consider that it's a little more fuzzy than that.