On a downswing people associate more negative value to bad outcomes than positive value to good outcomes. This imbalance gradually shifts overall disposition.
Every lost race goes from a 50/50 coin flip to a personal attack from the universe. Often the "universe" takes a more tangible form. You blame the dealer or become convinced the site hit the doom switch against you.
The best medicine to combat this imbalance is self-awareness. We must be cognizant of our own reactions to absolutely everything. As fast as one hand is over, two new cards come our way.
Lingering pessimism will affect current and future hands. Negativity leads to scared or reckless play; both poor options. The tilting is rooted in the initial imbalance of (supposed) objectivity.
Overlooking objectivity is the reason tilt is often so long lasting. Recalibrating the scale, with continuous effort, will yield better short and long-term results at (and away from) the poker table.
Consider a live cash game. Your stack was crippled early but you've been playing well. You saw your pocket kings get cracked by pocket 7s and without steaming off the remainder, you manage to double up a few hands later.
After close to an hour you find your stack is back to where it started and although this isn't really something to phone home about, you feel pretty good. Then, inevitably, a big hand says hello and introduces itself.
You defend your BB when the SB min-raises. You're holding J-T suited. Your opponent has been fairly loose-aggressive and has an affinity for the gambling side of the game.
You're pleased to see the rainbow flop lands ten high (T, 8, 5). The SB makes a small bet. You make a pot-size raise and get suspicious when he calls.
The turn card is a 7, giving you a gutshot straight draw. His passive tendencies on this hand come to a halt and he leads out on the turn with a big bet, nearly 1.5x the pot.
It's time to think. Contemplating your decision, your opponent speaks up to try and cloud your judgment.
His jabber oozes a verbal tell when he asks "Let me guess, Jack-Ten?" His prediction is spot on. Soul read? Maybe, but it doesn't really matter. What's more important is why he would do such a thing.
By making such bold predictions, whether true or false, players actually offer more information on their hand than yours - especially if you keep your mouth shut.
His guess makes you suspicious. You trust your instincts and make the fold. Being the good sport he is, he shows you A-T. Your fold was absolutely correct as you were an 85:15 underdog after the turn.
The feeling after a fold like this is usually ambivalent. Losing money sucks, but saving chips is good. In the long run, at the end of the day, your pockets will thank you. Your confidence will grow knowing you can make good reads and follow your instincts.
This phenomenon, however, is relative. Much like an idle elevator is only appreciated compared to having to wait (see: Variance and Elevators), so too a folded hand feels good only when you think of what you saved.
In life we're presented with infinite possibilities in any given scenario but can only choose one. Once we act in the present, those actions become the past. If we're presented with choices that offer immediate positive or negative returns, like we do in poker, we have an instant grading scale to show us how we're doing with regard to our choices.
If we make a good decision that saves us money (i.e. making a good fold) we save/gain monetarily but are internally displaced very minimally. But if you take the exact same hand as above and call or raise on the turn and lose the hand, you come away extremely agitated.
Why then, after a great fold and avoidance of that agitation, do we not benefit to an equal degree internally? Some argue it's because the hand is still lost and any loss brings dejection. Others realize that since the extra chips weren't lost, we can't truly feel the difference.
The absence of the pain is not felt as a positive; the bad thing (calling the bet) never happened so we can't experience the reverse (which is joy) from it except in the hypothetical.
Imagine a parallel universe and replay the hand as Player 1a and Player 1b. The hand finishes and what do we find? Expectedly Player 1a's disposition after the fold (compared to Player 1b who called and lost more chips) is relatively more pleased even though he also lost the pot.
Since we can only exist in one reality/universe at a time, we instead rely on our imagination or memory to make such comparisons. The difference, from an internal entropy standpoint, is our imaginations or memories don't yield the same magnitude of displacement.
The freshness of the effect is what gives the bite. It's what makes us feel alive.
Analyze the way you view the game as much as you do the decisions you make. Consider alternative outcomes when reviewing your decisions. Doing so will increase the affirming actions you've executed and reduce the negative impact from the bad outcomes.
Being naturally predisposed to sulk in misfortune, we need to make a concerted effort to appreciate our good decisions and good fortune. There's no harm in patting one's own back when it's truly deserved.
Just make sure you stretch first; shoulders aren't meant to bend that way.