When I win or lose a lot quickly I feel the need to stop playing

I usually think of each poker game as one of many that in the longterm will be profitable for me, but when I win a lot in a short amount of time (I play sngs) I want to quit because I am already at or ahead the target i've set for myself. When I lose a lot early on I also like to quit because I tell myself I am not playing as well as I should be (which is sometimes true). I don't want to think this way, but find it hard not to. Anyone else have this problem or some sort of way to get your mind away from this type of thinking?

The problem isn't knowing what to do, it's the execution.

Perhaps I'm missing the point, but Poker, for me, is all about control of yourself. If you don't feel confidant sitting down at any table, then you shouldn't be sitting down at all.

When I win a lot, I feel the need to stop, but when I lose a lot, I feel the need to keep playing.

[Benoit]

I try to decide whether I will keep playing based on the game and my time restraints. But other things end up playing a part as well sometimes. Like last night the table wasn't that good anymore so I was ready to quit, but I decided not to just yet because I was just a few points from clearing my bonus... I actually could have finished clearing it another day at a better table, but I wanted that accomplishment on top of my session.

[Scorpion]

If you have a set target why would you continue playing? Maybe you should set a time target instead?