Winning Interpersonally

cousin_it would like to know how rationality has actually helped us win. However, in his article, he completely gives up on rationality in one major area, admitting that "interpersonal relationships are out."

Alex strenuously disagrees, asking "why are interpersonal relationships out? I think rationality can help a great deal here."

(And, of course, I suppose everone knows my little sob-story by now.)

I'd like to get a read from the community on this question.

Is rationality useless -- or worse, a liability when dealing with other human beings? How much does it matter if those human beings are themselves self-professed rationalists? It's been noted that Less Wrong is incredibly male. I have no idea whether this represents an actual gender differential in desire for epistemic rationality, but if it does, it means most male Less Wrongers should not expect to wind up dating rationalists. Does this mean that it is necessary for us to embrace less than accurate beliefs about, eg, our own desirability, that of our partner, various inherently confused concepts of romantic fate, or whatever supernatural beliefs our partners wish do defend? Does this mean it is necessary to make the world more rational, simply so that we can live in it?

(note: this draft was written a while before Gender and Rationality, so there's probably some stuff I'd rewrite to take that into account)