4. Casablanca
Ugarte: You despise me, don't you? Rick: If I gave you any thought I probably would.
Peter Lorre's character Ugarte in Casablanca is involved in some pretty shady stuff, and at one point in the film he woefully asks Rick if he hates him. It's a self-indulgent moment where the character is pretty much just wallowing in self-pity, which is why Rick's response is so perfect. When you hate someone, you're devoting a lot of time and energy to thinking about them. Hate is exhausting. So what Rick says here is that Ugarte isn't worthy of his hate. He doesn't think about him enough to hate him. Rick only has room in his head to hate people that matter, and Lorre is so cripplingly insignificant that the idea of hating him never even came up. There's no better way to put down someone than to remind them that they are not even worthy of your notice.