I've only got one nerve left, and you're getting on it.

I've seen people like you, but I had to pay admission!

Look, don't go to a mind reader; go to a palmist; I know you've got a palm.

Make a mental note . . . oh, I see you're out of paper!

Make somebody happy. Mind your own business.

Are you always so stupid or is today a special occasion?

Are you brain-dead?

Are your parents siblings?