I think that we need to gain experience with different bets, different situations with losses and big wins, after which we will not be too interested and it will not cause us too much emotion, and when emotions are at a low level, then we can concentrate on more reasonable and balanced decisions. In addition, some can be helped by various things like watching how others win or lose huge amounts and imagining what would happen to us if we were in his place. Although it may not help some very much.
Imagining or seeing how someone else win a huge amount of money from gambling can only draw the person to want to gamble much more and nothing else, this is not a way to practice emotional control or whatever but rather a way to encourage the person to gamble even the more.
I personally think that when it comes to practicing emotional control, this has nothing or very little to do with wins especially, because wining only encourages one thing, and that is more gambling, it doesn't matter whether we are the one winning or someone around us, when you win yourself or you are around someone who won from gambling, this makes you want to gamble and gamble the more to try to win more or win too.
Emotional control in gambling is something we must never relate to our gambling outcomes, else, we won't master it, that is, if we always need a win or a loss to master emotional control, we may never learn to put our emotions under our control.