This is kind of a spin-off thread from Gero's post.
For me, I have learnt that if a girl isn't articulate and eloquent, and witty, attraction will wear off pretty damn fast. She could be the most wonderful woman in every other sense, but if she can't put up a good wordy fight I'll end up bored.
ALSO people unwilling to try out different foods. I once went out with someone who described prawns as 'pretty exotic', and wouldn't eat anything with any kind of seasoning. Maddening.
What are your bugbears, team DiS?