THE BLOG
02/25/2013 10:55 am ET | Updated Apr 27, 2013

7 Things You Didn't Know About Your Friends

Sure, you're up on everything from their favorite soups to their most shameful secrets. But you probably haven't thought much about how your friends are quietly and unassumingly coloring key aspects of your life. While friendships are mostly cherished, few of us are fully aware of the specific effects friends have on our personal growth and happiness.

In my book Friendfluence, The Surprising Ways Friends Make Us Who We Are ($25.95, Doubleday), I survey the ways friends shape our personalities, health, aspirations, values, and habits throughout life. It's a particularly good time to think more consciously about how your friends influence you--for better and for worse--because they are increasingly taking on roles traditionally fulfilled by other kinds of relationships. We're marrying later or not at all, and we're living alone or with friends more than people of previous generations did.

Knowing the minutiae of your pals' tastes and quirks is a privilege, of course. But here are some non-trivial truths about those friends of yours:

7 Things You Didn't Know About Your Friends