Bloke goes into the library and asks for a book about the art of repartee. It's lunchtime and the trainee librarian is at the desk and hasn't got a clue about what the art of repartee is. "Well," says the bloke, "repartee is the skill of the quick come back, the witty remark." Blank stupidity remains on the assistant's face. "I'll give you an example," says the bloke. "My brother in law, he's got the art of repartee. We all went to the circus and got front row seats. So when the clowns came on we were right in the firing line. One clown was working the audience and taking the piss out of people. He came up to my bother in law and said: 'Tell me sir, are you the back end of an ass?' My brother in law, guardedly, says 'no'. The clown goes on: 'Are you, sir, the front end of an ass?' My bother in law says: 'no' again. 'Then sir,' says the clown, 'you are no end of an ass!" To which my brother in law, as quick as a flash said: 'Why don't you fuck off?'"