
I have the very same problem! And what makes it even worse? I say i will leave at some point, then i decide to stay and end up winning a bunch!
I think the best thing to do is to stick to whatever you set though. I have also lost more when not being disciplined. Personally, my limits are:
4x whatever i bring in,
2-4 hours
if i lose what i bring in, i'm done.
if i have 4x what i brought in in my pocket, i will use whatever is left over as "play money" until i hit one of the other limits.
What is so nasty about going to casinos is that afterwards you look back and see how cloudy-headed you can get after many hours of play... but at the time you don't realize... if you get a good win you should walk around, dring something (water, etc), take a restroom break, use some comps on some food or something!! The more refreshed you are the better you will likely do and the more fun it will be!
I have played for 8 hours straight before... i at the very least stick with basic strategy, but my betting strategy becomes very risky. I end up being like "it will turn around the next hand, so i will bet max! lol"
The betting strategy that has worked the best for me so far on a 4-deck shoe... start small, build up if the shoe is paying out... and at Treasure Island in redwing, minnesota... they don't shuffle nearly as thoroughly as i have seen at other casinos. I swear that a good shoe tends to stay a good shoe and a bad shoe stays bad for a quite a while. There is a chance a shoe can turn around... but last time i went, i sat down on a 4-deck shoe and lost most hands in a 6-hour period. i switched tables on the last shoe before it was about to be closed down, i won almost every hand (6-deck), i switched to another 4-deck shoe and it was hot the entire night! i won everything back and more! In the previous times I went, i have found nice tables which keep on paying out... i end up building up to table max ($195) and just keep winning them!
Its a wonderful feeling when they have to bring out black chips to refill the chip tray

Now if only online casinos had as good of odds as a real table with a 4-deck shoe...