That means the key is always about "managing and controlling" isn't it? Well that's obvious, in any case and not just about gambling, everyone has emotions and it's normal for them to occur due to something that's not what you expected, but if it happens excessively then obviously it's not good and will actually cause a lot of new problems, and also on the other hand we have to understand where we are, or we mean we have to understand that this is gambling which is always about winning and losing.
So it's ridiculous behavior if you're overly emotional about losing, and I would probably say that you're not a responsible gambler. And the point is like you said that the only way if they don't want to experience dominating emotions is that they should gamble moderately and reasonably in the sense of only putting an amount that will not make them angry if the money is lost in the end, and I believe that treating gambling with some of the suggested actions will be easier to do when you make gambling as a suggestion of entertainment, because then I am sure that you will not think of doing excessive actions and also I am sure that you will not be too dominated by emotions when the results do not match.
Yes, managing and controlling is the key to playing gambling with fun and that will us to control emotion not to become high. Playing gambling can makes our emotion become high but with learning about controlling, that doesn't makes us lose self-control. We can't expect having a good experience by playing gambling and win because we can lose many times and we will not feel happy when we see that. But if you can learn about self-control, you will not face that because you will not breaks your rules just to chase the win.
By always limiting our gambling activity, we can prevent becomes too emotional and we will not playing gambling too long or with bigger money because we know that can attract us to use a big bet that can cause us losing the money. We must learn becoming a responsible gambler to prevents anything that can lead us to have trouble when we playing gambling. With self-control that we learned and practiced, we will always holds ourselves by not placing a bet with too big money because we know that can gives more losses. Many gamblers already have that experienced and we learned from them so we can prevent it and not happens to us. We can also treating gambling as a fun activity because that is the truth so we will not break our rules.