(Alvy, the protagonist, is confronting Annie, his girlfriend, about having an affair with a professor at her college)
Alvy Singer: Oh stop it, you're having an affair with your college
professor, that jerk that teaches that incredible crap course, Contemporary
Crisis in Western Man...
Annie Hall: Existential Motifs in Russian Literature. You're
Alvy Singer: What's the difference? It's all mental masturbation.
Annie Hall: Oh, well, now we're finally getting to a subject you know
Alvy Singer: Hey, don't knock masturbation. It's sex with someone I love.
Laugh Away... Transcript obtained from IMDb quotes page.