I can't easily stop when I am losing despite the fact that I already set up a limit to gamble in a certain day or a certain session.
This is why leave gambling so hard and they chose to stay for more winning. Every gambler will break his rules and limit if can't control his emotion, revenge first loan later. Stop is about mindset and family ( society ), you need both to stop. If you choose stop after win/ loss I'm sure you'll come again, stop is stop and leave forever.
Therefore, professional gambling players simply need plans and strategies full of restrictions and limits.
Thus, the player eliminates the role of emotions during the game session due to the fact that follows a strict, simple, and understandable plan.
The vast majority of players use such strategies, therefore the level of gamblers is so high.