ACE: Sometimes I think it’s you that’s crazy, not Deadbeat here.

THE DOCTOR: Anybody remotely interesting is mad in some way or another.

Doctor Who (1963-1989) British science fiction television series, original run (BBC)

25×04 “The Greatest Show in the Galaxy,” Part 3 (1988-12-28) [w. Stephen Wyatt]
    (Source)

See Aristotle.