That disappointment is also teaching us how to be patient and to control our emotions.
If someone who gambles and yet not ready for disappointments, they'll experience the baddest day ever in gambling soon.
They should be prepared for that because there is no coming back when they ever experience that.
Disappointment establishes the realization of wrong fact about gambling, I believe a lot of gamblers has seen other people who hasn't been long on gambling but are already looking up to the huge money gambling had for them in the future but with several disappointment it will differently make the gamblers realized that they have wrongly been misleading themselves with hope of future wining that might not be won, so that's what disappointment does for people like that so that they would leave assumptions and face the reality of things, disappointment is a fact in gambling that everybody must see.