First thing you need to do is remove any attitude you may have from your game, and I mean that in general, not trying to say you have an attitude. There are a lot of people that aren't as good as they think they are and when they begin to lose to someone that they think they should be beating it gets under their skin. Likewise, you may actually be better than that person and are losing and it gets under your skin. One thing to always remember is that everyone loses to higher level and to lower level players. You can't win every single game you get into, and you won't. That's a cold hard fact. There are tons of reasons for it too. Maybe you're just having an off night. One thing is for sure though, if you dwell on what happened before then you are not focusing on what is coming up. You can't come to the table and run it out if your focus is on the hanger you just missed. No matter how hard you try, no matter how angry you get, no matter how many ways you try to figure it out, that last shot is not coming back and changing for you. Only thing you can do is make note of it for a later practice session so you can reduce the chances of it happening again.
If I can offer some advice, or tell you what I used to do to keep my blood from boiling. 1 thing I used to do before a tournament was sit out in the waiting area with a needle and thread. I would thread that needle over and over and over, for at least 10 minutes, before my match started. To thread that needle you need to concentrate and remove any other distractions that may be going on around you. I know, you feel like an idiot, but you'd be surprised how focused you get on your game after doing it.
One other thing I used to do is when I sat back down I'd focus all my attention on the chalk sitting on the rail. Wondering where it's been, how many people have used it, why does it have that nick taken out of the side of it, etc... I would think of anything other than the shot I just dogged. Again, because it's not coming back to fix itself.
Another thing to do, and probably the best, is when you get back to your chair use that time sitting there to run out the table in your mind. Tell yourself exactly what you're going to do when you get back to the table. A lot of times that rack will finish before you get that chance to try what you were thinking about, but at least you're focusing on what's coming up and not on what just happened.
Last but not least, unless you're actually losing your rent and your kids are going to go hungry from this loss, does it really mean anything? The world isn't going to come to an end because of it, the Mayans have taken care or that anyway come December. hahahaha!!
Seriously though, I'm one of the most level headed people you'll ever find. I just don't let things bother me. I think because I just don't care enough to let it. I may be lucky in that the majority of my playing career has been in Japan. People aren't as likely to try sharking you as they are in the States. I've been playing over here for 21 years, and I used to play at least 4 hours a day for a span of about 10 years, and I've only run across 2 people that were brash enough to try any type of sharking. It's just not common here. It's the exact opposite really. The Japanese players actually apologize to you for their poor play. Even if they purposely hook you behind a ball, and you miss hitting it, when they return to the table they will apologize for making you miss. I think a lot of Americans can't handle that when they're playing over here. They almost take it as being sarcastic, which it isn't.
MULLY
I should make a video about playing pool in Japan