" And the fundamental idea is that your close friends are wonderful for all kinds of things—for giving you support, for helping you when you’re sad, for doing favors that other people wouldn’t do for you—but as sources of information they’re not very good, because your close friends tend to know the same people you know. Whereas people who are just your acquaintances—who might not help you out if you were in desperate trouble—are still better sources of information because they know so many people you don’t know. They’re really your windows on the world, because they’re linked up to different circles from your own. "

― Steven H. Strogatz , Sync: The Emerging Science of Spontaneous Order