All I did was ask for half caff. Our waitress glanced toward the kitchen miserably, like I’d just added an hour’s worth of work to her day. I looked around at the spattering of others in the restaurant (hardly a rush); then, when she walked away, I leaned across the table and whispered to my friend, “She’s a grump.” Maybe. But this was also an opportunity for me, and I missed it. Two days later I...