How can something so simple be so profound, letting others go first, in traffic or in line at Starbucks, and even if no one cares or notices? Because for the most part, people won’t care—they’re late, they haven’t heard back from their new boyfriend, or they’re fixated on the stock market. And they won’t notice that you let them go ahead of you. They take it as their due. But you’ll know. And it can change your whole day, which could be a way to change your whole life.