SLARTIBARTFAST: I’d far rather be happy than right any day.

ARTHUR: And are you?

SLARTIBARTFAST: No, that’s where it all falls down, of course.

ARTHUR: Pity, It sounded like quite a good lifestyle otherwise.

Douglas Adams (1952-2001) English author, humorist, screenwriter

Hitchhiker’s Guide to the Galaxy, Phase 1, “Fit the 4th” (BBC Radio) (1979-03-29)
    (Source)

This is novelized in The Hitchhiker's Guide to the Galaxy, ch. 30 (1979), with the same dialog.