Before even walking into the casino, I'm already expecting the lose all the money I'm going with, so if that eventually happens, I don't see any reason why I should get angry or feel somewhat way about it because I already saw it coming.
Gambling is a 50/50 thing, and while you're hoping to win, you should also expect to lose, and that's why it's very risky to gamble with money you can't afford to lose because if that happens and you lose money meant for something else, you'll not only get angry, but also frustration and devastation too.