The Last Wave: A movie that picks one theme, one type of imagery, a few motifs, and employs them systematically through to the end. In other words, a masterpiece.
If there's a single problem with film today, it's the inability to follow through on only one idea throughout a movie. Better to gesture towards a half-dozen things, all undeveloped, in order to better reach the audience. (Also NB: one idea can be sustained well for no more than two hours.)