Man 1: "Do you wanna hear a joke?"
Man 2: "Yeah, alright."
Man 1: "Okay. What do you call a Scottish terrorist group."
Man 2: "Dunno. What?"
Man 1: "Och Aye-da."
Man 2 gives the kind of nervous half laugh you give when you really don't find a joke funny but don't want to disappoint your friend by letting them know they've just told a really fucking terrible joke.