When you are expecting to win and turned out that luck isnt on your side on that particular moment, then you will be ending up on having that kind of disappointment and frustration because it is opposing on what you are that anticipating into. Its important that you do really need up to consider that losing is most likely that will happen on gambling or the rate of losing is way more than on what you do able to win up. You wont get stressed if you arent that expecting something positive then these loses will be that not a big issue for you and you do rather found yourself that easily moves on and wont be having that any impulsive actions that be taken or any something that will be putting up you into danger specially when it comes to financial aspects on which its always been best to have this kind of thinking or approach rather than on making yourself that being that too positive into something that didnt happen on which it do bring out that frustration.
A good way to avoid getting shocked and facing tense conditions is to expect less.
You have a good point, but it may not be as simple as just to expect less, some conditions must make that possible. Most people have positioned their minds too high in gambling and the profits associated with it. This is why they commit big amounts of money to it. Now tell me, can the person who bet/risk big expect less? That's the issue, because such a gambler did not gamble with the amount of money he can afford to lose, and no matter how he wanted to fight his psychology to stay calm and expect less, the emotion attached to that big amount will not let him.