Which fantasy novel taught you about being a good person?

We read fantasy books for all sorts of reasons, including escapism, gritty action, and immersion into detailed, ornate worlds. But one great reason to read fantasy novels is because many of the genre's best works deal with how to be a good, ethical human being.

So I was wondering — what's the fantasy novel that you feel did the most to teach you about how to be a good person? (For me, it was probably Ursula K. Le Guin's A Wizard of Earthsea.)