Edward Hoagland in The American Scholar:
We need roommates to get through college and afterward somebody to leave our keys and goldfish with. Friends may indulge us a little because they know our soft spots—the son in limbo after a meth arrest, the mortgage underwater, the trial separation, the cancer scare. Gossipmongers, by contrast, are permitted in polite society because they furnish narratives of indignity where but for the grace of God go I. We’ll tug a restaurant check away from a friend and bump shoulders in the parking lot, but when in love our eyes fix unqualifiedly upon the other person’s, wide open for inspection, not veiling hurt, confusion, or longing. A current flows, impulses are telegraphed, a flutter of distress crimps the mouth even before we know why. By middle age, our countenances contain a toolkit of engraved expressions, from deadpan stoicism to blithe equanimity. At weddings, funerals, we sit in the pew, while, as on a much-plowed family farm, the grooves to accommodate whatever is tossed at us lie in our faces already.
Friendship is protean. Your children, foodstuffs, and weak points are safe with me, and I’ll keep watch while you sleep, was how it all began; and primeval wellsprings of suspicion are still aroused when people lack friends. It’s why we brag about how many friends we have on Facebook, or how many people might put us up all over the world. Allies are necessary in early jobs to speak up for you, explain the ropes, and then it’s a leisurely, exploratory process where you lay your cards on the table, gradually seeing if they complement the other bloke’s. Yet loneliness peeps over the horizon for most of us eventually.