Luck is also based on the type of game chosen, If you continue to play Slots and you only get a loss then you really haven't been lucky and the system hasn't given it to you,
But there will still be a chance to be able to win if the gambling is indeed Legit and actually gives the player a win.

Setting expectations so that they are not too high is indeed a good way to overcome greed or not expect too much of a big win,
just look at how the game goes and don't be influenced to keep adding money to the game when you keep losing, management needs to be done so as not to spend too much money without winning.