"Better luck next time." "Did your nurse teach you how to tie your shoes, too?" "When I stop laughing, you can try again."
Make up whatever you like to tell him off. Sarcasm is usually the best. The most common is, as stated above, "Is that the best you can do?"
Replies which show a sense of humor would tend to diffuse the intended purpose of upsetting you. And if you can make a joke at your own expense, (not injury) instead of the other person's, it might not cause him anger and thus increase the tension.
Eleanor Roosevelt once said, 'no one can make you feel inferior with out your consent.'