Well Wii I know he meant it in a teasing way but you are right it was not very mature of him...
I mention it because his "teasing" always seems to be in ways that reinforce the idea that you're dumb. It's not a one time thing for him but a pattern, which I see as emotional abuse. Even when he does a nice gesture (which I think is part of an ongoing stealth campaign to keep his bread buttered on both sides...sorry I'm no Dan Fan!) he has to spoil it by a big "Duh". Anyway, just my initial reactions to what I read...take it or leave it