Hollywood so often caters to the lowest common denominator that it's not often we'll emerge from the cinema and be rather unsure of quite what we've just been witness to. Is this exclusively a bad thing? Does a confusing movie automatically mean that a director has failed? Absolutely not: there are plenty of challenging, even nonsensical movies which are superbly acted, gorgeous to look at and fascinating to dissect, even if there's no clear answer to the puzzle and audiences are left to make their own minds up. One can often imagine the directors of such films rubbing their hands with delight at how much they can dismay audiences. Such will apply to many of the movies on this list, whereas others may simply prove to be too impenetrable for some audiences. It's highly subjective, as more casual viewers may have found something like Inception confusing, where more seasoned cinemagoers may have appreciated the intellectual workout. These 10 movies, however, have stirred up fervent debate online ever since being released, as viewers have scrambled to uncover their true meaning, even though there really may not be one. Did we miss any classic cinematic brain-busters? Or were these movies a lot easier to understand than we're letting on? Let us know in the comments!