One of our coaches for waterpolo used to also be a professional referee, even at the Olympic level. It's not often you have someone in such a position on the coaching staff. She always used to tell us to never talk back to the ref, ever. Luckily with waterpolo you have something that is pretty good at muffling the sound right beneath you. Whenever a decision doesn't go your way, and you have something to say about it, all you have to do is put your head under the water and let it all out. This in itself goes a very far way in calming you down, and since there is no one to hear it, it's also entirely victimless.

Before long, you come to realise that you can forgo this very process if you give yourself enough time to let the feelings lapse. If you just pause, take a deep breath, and then continue about your day, often this is enough. There are times when this doesn't work, however, and you need to stop and think before responding to impulse, and in the very worse cases, you may need to find a nearby equivalent to a pool to let the emotion out. These momentary lapses of judgment can be very damaging if not controlled, so it helps to be conscious when the feelings arise, and to just let it subside uneventfully.