What is your favorite trope in SF/F?

[E.A.]

-I like military space opera, where not everyone on the protagonist side is a good guy, and not everyone on the antagonist side is a bad guy. Where there's a flavor of espionage and a description of how politics influences military actions.
-I also like anything humorous. Whether it's science Fiction (Robert Sheckley/Keith Laumer) or Fantasy (Terry Pratchett), I'm always game for a good laugh.
-I like Urban Fantasy where ancient gods/spirits are walking among us in the current world, unbeknowst to most people, and then something Earth-shattering happens.