I know this was mentioned, but I want to say it again. LAUGH, LAUGH, LAUGH!
Laugh out loud and just smile at yourself.
Jw
There is another benefit to this that I don't think anyone has mentioned yet.
If I'm playing a match, and I see my opponent blow up over a missed shot, I;m pretty confident that when he gets back to the table again, he may not be as focused as he should be. He has allowed his emotions to get the best of him, and that is to my advantage.
If you walk away from a missed shot with a smile on your face and a calm demeanor, you are sending a message to your opponent that your confidence hasn't been shaken, and you will be ready when you get back to the table.
A calm reaction to a bad situation can actually disturb the mental state of your opponent. If they think you are unshakable, they may end up putting more pressure on themselves.
Steve