Every day, Glen purchases his morning coffee at a nearby drive-through. And every day he also pays for the order of the person in the car behind him, asking the cashier to wish that person a good day. Glen has no connection to them. He’s not privy to their reaction, nor, it seems, is this his motivation: he simply believes this small gesture is “the least he can do.” On one occasion, however, he learned of the impact of his actions when he read an anonymous letter to the editor of his local newspaper. He discovered that the kindness of…