Guts is arriving home late after a night out with the lads, being assaulted by your wife with a broom, and having the guts to ask: "Are you still cleaning, or are you flying somewhere?"
Balls is coming home late after a night out with the lads, smelling of perfume and beer, lipstick on your collar, slapping your wife on the arse and having the balls to say, "You're next fatty."
