The excitement of winning is really overwhelming and require lots of discipline to stop at that point before incurring lose weightier than the win.
But I think why some can't or won't stop is not all about the excitement but is about the greed of wanting more when it is even obvious that the next try is totally uncertain and blurry
It is hard to stop feeling excited when you are winning and you are getting real life benefits like money. If let's say a father started gambling and he is able to feed his family and buy their wants and needs because of his winnings, it is hard to control that excitement and he will surely continue it even more.
If you ask me when is the best time to stop, I will say it is when you are high on the joy or excitement and calm down before going again but not same day or even week
When you are high on adrenaline, it is hard to think properly and you might make decisions you will be regretting over time. So, calm down before you make another bet.
Excitements will come and we must feel it, show it and also be able to control it, the way some gamblers have been leaving their life is not worthy of emulation, because of high level of indiscipline even at the stage of being excited, we should learn to do things accordingly and in the appropriate manner, so that we don't get into something else in a wrong way, gambling should be what we all have to learn to enjoy and never take for granted and ended up being in regret over it.