A recent grocery run in Brooklyn left me properly confused. When I approached the registers, little coconut waters in hand, two options presented themselves: I could get in the self-checkout line, in which dozens of headphone-wearing customers thumbed through their phones. Or I could go through the staffed checkout lane, which had no wait at all. What a bunch of schmucks! I thought. I breezed through the cashier’s lane and was soon out the door, while many of my fellow shoppers remained in self-