From what is probably my favorite sci fi movie, Forbidden Planet:
Commander John J. Adams: Morbius, that thing out there – it’s you.
From Naked Gun:
Mayor: Now Drebin, I don’t want any trouble like you had on the South Side last year, that’s my policy.
Frank: Well, when I see five weirdos, dressed in togas, stabbing a man in the middle of the park in full view of a hundred people, I shoot the bastards, that’s my policy!
Mayor: That was a Shakespeare-In-The-Park production of ‘Julius Caesar,’ you moron! You killed five actors! Good ones!