My dad taught me chess when I was in the second grade. By fourth grade, I was beating him half the time, sometimes more during our marathon sessions. Somewhere in-between, I got cocky. I remember one game where he failed to notice his queen was under threat, and I told him so just as he was about to make a different move.   Dad wasn't pleased.   He said gently, “Next time you do that, I won’t play with you. In chess, never tell your opponent his move or that he’s making the w