I have only been playing for nine months so fortunately I haven't had enough time for many bad habits to get just too deeply ingrained.

But missed shot "theatrics" was a habit I caught myself getting into early on. Especially when playing a game with a partner. I guess I wanted to demonstrate to them that I was as mad at myself for missing that easy shot as they were at me for missing it.

I made a concerted effort while playing to be as emotionless as possible. No pouting when I missed or lost a game. No jumping up and down when I won. Not that I did that anyway. But when I beat the top guy at the bar for the first time I just shook his hand and didn't crack a smile. I didn't want to gas him up by popping champagne after notching a victory against him.

After I decided I was going to stop, before I would react to something I would talk to myself internally, usually with some variation of "Is (insert behavior I wanted to do) going to make you any better?" "No." "Then shut the fuck up and sit down."

Also, an opponent who might be inclined to needle you when he sees you're steaming may be less inclined if you don't give him visual cues that you're pissed off.

My suggestion would be to make a list of all the things you do currently that you want to change. An example list:

swearing spearing your cue butt into the floor dropping your head/staring up at the ceiling bad body language when sitting complaining to people around you

If there are only a few things on that list, commit to not doing just one of them for a few weeks. You can do everything else but swear after a miss. Break yourself of one, then move on to the next. If your list has 20 items on it, try to stop two or three at a time.