Whether a film becomes more obscene the more swear words it contains is arguable: presumably the law of diminishing returns kicks in at some point. As the late film critic Roger Ebert once pointed out, when you’ve heard one f-word, you’ve heard them all. But film classification boards on both sides of the Atlantic disagree: the Motion Picture Association of America (MPAA) and the British Board of Film Classification (BBFC) rule that teenagers’ films must have fewer than four “fucks”. More important than numbers is context: “fucks” can only be used as adjectives in such films, preferably in humorous contexts, and never as verbs. Who says grammar isn’t useful?
