Waiting at the DMV yesterday, I watched a middle-aged man who I guessed to be a Native American, a middle-aged American white woman of indeterminate ethnic extraction, and a middle-aged American black man who looked to be a veteran, bonding over their love of chocolate. The American Indian man’s face split wide with laughter as they all shared their struggles with the same weight-loss program. Apparently, it limited their chocolate intake. The conversation began when the American black man spun...