"if closeness forms the basis of friendship, it stands to reason that your best friend would be someone with whom you enjoy supersized intimacy. but according to social psychologists, there's another component to best friendship that may trump even intimacy: social-identity support, the way in which a friend understands, and then supports, our sense of self in society or the group.

we become best friends with people who boost our self-esteem by affirming our identities as members of certain groups, and it's the same for both genders. men who derive their most cherished identity through their role as high school quarterback, for instance, are most likely to call a former fellow teammate 'best friend.'

we stick with people who support our social identity and withdraw from those who don't. we may even switch friends when the original ones don't support our current view of ourselves.

most of us would prefer to think that we love our friends because of who they are, not because of the ways in which they support who we are. it sounds vaguely narcissistic, and yet the studies bear it out."
-friendship: the laws of attraction-