Carolyn Hax is away. The following is a past column.Q: Why are all nice girls ugly and all the pretty girls not nice? Someone once explained to me that pretty girls get so much attention because of the way they look that they never needed to be friendly, while the ugly girls know the only way they’ll get attention is to be charming. I hate buying into these kinds of generalities, but I must say, there seems to be a certain truth in it.WashingtonA: Your theory, at least, is both untrue and ugly throughout — and your disclaimer doesn’t impress me. Does attention come more easily to people who are born beautiful, and does that stunt their character growth? You could argue that. But if there’s a generalization to be made (and then insincerely lamented), maybe it’s that pretty women develop defenses against relentless attention from guys who judge them solely on looks. If you want genuine kindness, then show genuine kindness, in venues where that has some value. Take sex off the table if motives are unclearQ: Three weeks into dating a guy, how do you know if he is after a relationship or just some bedroom fun?D.C.A: Oh, oh, I know this one! Decline to be a source of bedroom fun until you’re confident he wants a relationship. If that’s what you want from him.Sound like your granny? Maybe. But only if your granny believed in making choices based on immutable human law instead of fungible social mores. If you want to be treated a certain way, which approach makes more sense: insisting on it and then backing that up with your actions, or putting it entirely in someone else’s hands and hoping fretfully for the best?