Quentin joins an orchestra as a violinist and sits next to Sebastian during a run of concerts. Night after night they sit there, in their black suits, and play the pieces. During a long rest in one of them Sebastian turns to Quentin and say "do you know what? I am so fed up of sitting in this uncomfortable suit with my black bow tie, black socks and black shoes. Tomorrow night I'm jolly well going to do something about it".
Quentin says "good heavens, old chap, what on earth can you mean? What are you going to do?". "Just wait until tomorrow night", says Sebastian, "I'll bally well show them".
The next night comes and there's Sebastian in his black suit, white shirt an bow tie. When they get to that same long rest, Quentin asks "what happened to your resolve, old fellow?"
With that, Sebastian lifts the leg of his trousers to reveal a yellow stripe on his socks. "Great scot, what have you done" says Quentin.
Sebastian turns to Quentin and says "f**k 'em".