Indeed when you are playing gambling in the long right you feel boored and try to bet all your money in single shot and then feeling lose after loosing all your money 
it's already profit but it's gone and it's become stone the wissest gambler i know is they always withdrew there profit and then comeback when they sure to gambling again.
In the long run discipline is the most important factor I think, There's aways be a periods of time when we feeling unlucky (longer) and of course sometimes very lucky(shorter), the secret is cutting the losses in your bad days... by accepting what you already lost and just stop playing waiting another day (easy to say hard to do kind of thing) it's already profit but it's gone and it's become stone the wissest gambler i know is they always withdrew there profit and then comeback when they sure to gambling again.
i agree. most of the time we can't control the result of our gambling. and when you play in casinos both online or on site, you also play against the house's advantage so really there's no win win situation for a player. it's a different case though when you have your own gambling site. so for us regular gamblers, i agree that the focus is how to manage our bets so we don't lose that much in case we're not that lucky on some days