The common expression goes "you can choose your friends but you can't choose your family" (or something like that anyway) but can you choose your friends?

When I think about most of my friends (many of whom I obviously like immensely) I'm by no means I'm convinced I ever made a conscious choice to be friends with any of them; we just sort of fell into a pattern of being friends after a while.

So do you think you do choose your friends?