For me, it's about tilt, bankroll management and focus. Too often, I'll rematch an opponent over and over again when losing... sometimes even after 10 buyins. Moreover, I don't move down in stakes when my bankroll and play suggest I should. Finally, I often play when not focused, such as too late at night when I'm about to fall asleep and playing terribly (just trying to end games with big moves or bad hero calls). For instance, just a few hours ago, I played a session during the morning (not that I slept) and lost almost $500 at the 52.50s to players I'd normally crush. The sad part is that most of it wasn't luck.Having outlined this publicly, I hope to make the necessary changes.1. Don't play when you feel tilted, take a break. There are certain physical signs I notice when I begin to tilt and even though I can control their effect on my game, it is tough and not wise... especially playing someone with momentum. In fact, maybe it's best not to rematch someone after two straight losses because of the momentum making it harder for me to play well. On the other hand, if it's a fish, perhaps I should suck it up and play more games anyway. This is a really tough question. If you see a losing player with -5%+ ROI and lose two games... should you really stop when it would be expected you have an edge and you don't feel tilted?2. Move down with less than 30 buyins if you're not extremely comfortable. Never play with less than 15 buyins unless you want to bust 99% of your roll and have to play the 10s again.3. You know when you're tired and not likely to play your A game so just cut it out. Stop the one more game to get to a "pretty round number" syndrome. It never ends well. And even after I get to that number, I talk myself into playing more at far less than my normal game.Stop making dumb assumptions based on what you'd do! Just because you'd raise someone's first limp thinking it's weak doesn't mean he's doing it with air or that you should reraise, bet the flop and shove the turn when he calls. Similarly, a paired board doesn't mean everyone's bluffing you just because you always try to bluff them. Stop 4-betting their 3-bets with J8o on 449r and you'll save a few stacks. If the board turns really nasty and your opponent fires big or even goes all in, don't call because you think he knows you can never call with your top pair and that the value bet is thus too big to ever work as more than a bluff... they just have it. Stop being a hero, you're not actually saving lives. This all goes back to focus!