Cinema is full of grand, amazing imagery, but movie trailers often undermine this by focusing on it too much, to the point that by the time we're actually sat in the cinema watching a potentially iconic scene, we've seen it so much that we're sort of fed up with it, and definitely not surprised by it. Take the above trailer for Brian De Palma's superb horror hit Carrie, which doesn't just go about explaining the bulk of the narrative, but heavily references what is easily the most memorable and talked about moment of the film, when Carrie gets covered in pig's blood and a telekinetic ****storm takes place. In a YouTube age where we can obsessively watch a trailer until we're absolutely sick of it, filmmakers need to be careful of letting these sorts of things slide. The worry is that by the time we're sat in our cinema seat, we've been gorged on the fantastic imagery so much that it'll just evoke a shrug when shown within the movie. We'll be expecting something more and it won't happen.