Twenty years from now, a teacher’s one sentence might still be ringing in someone’s head. Maybe you’ll be the teacher.

One sentence can outlive the person who said it by decades, and usually the speaker has no idea which one landed. You probably carry a line somebody said to you in fourth grade, good or bad, that still turns up in your head at odd moments. The people handing those out are rarely being profound; they are talking on an ordinary day.

You are already doing this to someone younger than you, or to a friend in a bad week. Say the encouraging thing out loud instead of assuming it is obvious. It costs one sentence and might run in somebody for twenty years.