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

Terry Pratchett (1948-2015) English author

Sourcery (1988)
    (Source)

This quote is more often repeated in paraphrase, e.g., "What is there in this world that truly makes living worthwhile? Cats. Cats are nice."