Your little brother is taking notes on how you handle losing. That’s a legacy whether you signed up for it or not.

Losing is the most instructive thing you do in public. Winning looks about the same on everybody, but the two minutes after a bad result show whether a person blames, sulks, quits, or shakes hands and asks what went wrong. A younger kid watching takes their template from that, long before anybody explains sportsmanship to them. None of this asks you not to be upset, because being upset is honest.

Next time it goes badly, give yourself one watchable minute before reacting. Say the true thing out loud: that hurt, and here is what I would do differently. Then go be upset in private.