An extremely smart person I once spoke with said something that I always thought was very intriguing. Essentially she pointed out that the way the human brain works when a man and a woman meet is counterproductive: the more you like someone, the more nervous you are and the worse the impression you make. (My words, I guess she put it better.) I've thought about that a lot. I think that's why some people always end up with the wrong partner: people are attracted to confidence and the confident person who talks to you is not the one who cares the most about what you think about them.