I more often just lose interest and wana go do other stuff and wish MTT finish soon.
Shove it in with some krap and go -
"Well if this 27 wins this 3-way al in ok then let this be a sign for me to stay "
When you get a fair amount of well-timed cards, not getting dealt 28O, 29O, etc, it keeps you in the game mentally. The mental spark is enough to overcome the physical boredom.
But any variance, against you, the walls come tumbling down.
With no interesting cards, I suddenly remember it's been hours since I've eaten, drank anything substantial.
One hour of constant play, I'm hanging tough, win or lose. After 1 hour, I'm looking for any excuse to shut it down, especially if I'm playing cash, not an MTT.
When I play it doesn't usually happen to me, what I do is rest two days from playing or one and that always keeps me with the same enthusiasm and energy for the days I play, in case that happens to me when I play I put moved music, something wake me up
The more tables you play, the faster you will get tired. You can sit at one for quite a long time, and you may not notice it. I played the maximum amount of time for about 11 hours at one table without interruptions in the cash game.