Imagine this scenario. After a long drive to the airport, you’ve just taken off on a fifteen-hour flight. You’re in coach, and a family of three is sitting behind you—a man, a woman, and a toddler. They seem nice. But, as the flight continues, the kiddo grows restless. She kicks your seat and pokes her toys into your shoulder. “Stop that,” you hear the father say. The toddler, incredibly, quiets d...