Sometimes we can't prevent to feel that way, we are just human and we have emotions, it could be brought by different factors in our personal life but discipline is very important, we gamble for the main purpose of winning, therefore if we are not fully focus, there's always a reason to quit, but like I said, we need to be discipline, without that we won't be able to quit easily.
Yes, we are just people who find it difficult to control their emotions, but only because we have not developed this skill. Like any other skill, controlling emotions can be trained. This will not work out quickly, but if you constantly train it will be only a matter of time.
It’s enough not to allow yourself to express negative emotions. As soon as you experience a negative emotion for any reason, not only during the game should you become aware of it and go on to observe it, but not identify yourself with it. Over time, you will learn how to fully control your negative emotions.