BOB: I want to write a sketch
TIM: You can't.
BOB: I bloody-well can! Just you watch me!
TIM: No, I mean you can't. You just do not have the ability. Your characters are lame, the situations stink, the premises are all wrong. There's no conflict, the dialogue is crap and there's no soddin' laughs!
THERE'S A PAUSE.
TIM: I can write a sketch and I'll prove it.
BOB PICKS UP A BIG PIECE OF CARD AND WRITES 'A SKETCH' ON IT.
BOB: Ta-da!
END