Sourcery (Discworld, #5; Rincewind, #3)

by Terry Pratchett

And what would humans be without love?”

“I meant,” said Ipslore, bitterly, “what is there in this world that makes living worthwhile?” Death thought about it. CATS, he said eventually, CATS ARE NICE.

“Well, what he actually said,” she added, “was never enter an arse-kicking contest with a porcupine.”

“If failure had no penalty success would not be a prize,” he said.