We work on ourselves. Usually our mothers are sure to let us know all of our shortcomings and every little thing that might possibly turn off a man. Like that your pisiform bone is at an odd angle. Or that men don't like hairy toes. Or that your nose is too big. Or that your hair looks like witch hair or broomhedge. Or she'll just ask you if you stuck you finger in a light socket. She'll tell you to suck in your stomach and not stand with your gut pooched out.

I don't think many men get this assistance in childhood so they're unaware that they need to work on themselves until they start dating.