We can have the desire to win at gambling but we have to realize that it won't always happen. Maybe the few times we play gambling, we often experience defeat so we have to think that we should stop first to let go of the emotions resulting from that defeat. But usually everything will change after we get a win when we start playing, which will trigger us to continue playing gambling even though the decision to continue gambling can be the start of our losses in the next round. And we shouldn't be trapped by greed because we want more wins. And we have to overcome the greed that comes to us after we manage to win the first time we gamble.
Being greedy can really ruin us and make us bankrupt with nothing left because we will become reckless and decisive and we will lost even more so I think we need to be disciplined enough and also we need to make our minds powerful than our emotions so we will not go wrong in our decision, if we might be wrong still we will have the plan B that can be very helpful to us.
Well, the thing is, gambling does have its up and downs for everyone, there is always the negative side of gambling for every gambler, but like you have said, first, the outcome of a gamble or bet is not in the hands of the gambler to decide, this is absolutely certain and i believe all can agree with me, but then, how we allow the outcome of the game affect us or our emotions, very much depends on the gambler, it is like the common saying that "happiness is a choice", which means that, in every circumstances of life, be it a good or bad result, being happy regardless is our personal decision.
One way to overcome the aftermath effect of losing in gambling is to always remember, even before we start gambling, that gambling is nothing but for fun, if you win some money in the process, that is entirely your luck, if possible, never expect to win anything from gambling, so that if in the process you dont win, you wont feel too bad about it, but if you win in the process, it can make you more happier, as that could feel like money picked on the way side.