I used to enjoy grocery check-out time. Not anymore. For years, I'd put my groceries on the conveyor belt, a friendly cashier would say hello, we'd have a quick chit-chat, and she'd ring up my items. A bagger would then deftly slide my food into bags, and—when I was really stocking up—would even push the second cart out to the car so I didn't have to make two trips. Couple of jokes, couple of new acquaintances, fresh fish, beef, cheese, butter, eggs, a few other things, and that was it. All very easy—even enjoyable. But now, as with so many...