Be a good loser. I love playing netball, but if my team is losing badly, or if the other team is getting away with murder, I do a lot of muttering to myself, and only give half-hearted handshakes at the end of the game. However I don't argue with the umpire, or high-five my team when we're winning!
Wait patiently for anything. I might sit still and look calm, but I inwardly rage during health and safety briefings I've heard before, dull speeches, cinema adverts, waiting for wafflers to get to the point, predictable stories, red lights, traffic jams, queues... especially if I can't play on my phone. I go to a lot of trouble to avoid waiting, such as shopping or travelling at less busy times (but I never queue jump). Yes, I know, I'm a textbook product of the screen culture.
Go down a waterslide or similar just once. I have to do it again and again, like a kid on a playground slide who doesn't want to go home!