That kind of attitude display pains me to the bone marrow
Absolutely agree with you. I also do not like overconfident people when it comes to gambling as luck plays a very big role in this area. That's why you can never rule out that even a professional's bet may not play out. But I am very amused to see these overconfident gamblers at the moment when they lose their last money. The faces of these guys perfectly convey the resentment they feel.
Actually believing is good, but not good in some ways that must be forced when gambling. Too confident that they will win and get lots of jackpots. Even though it was just luck. Many make big bets and confidently laugh and belittle those who place small bets, even though every moment in betting such as football or horse racing can change, luck is the first. Feeling too confident will make anyone mentally down when they lose in the end.
There is a very popular saying that- it is good to be confident but it is very self-destructive to be overconfident, I find that to be true almost all the time. First of all, no one actually should gamble with the money that they worked really hard to earn. Secondly winning money by gambling is definitely not going to be a regular thing for anyone. But the thing is once you are winning, you are already hooked. You are going to gamble even if you keep losing, in the hope that one day you will earn so much that the losses are not going to mean anything, but sadly for most people that day never comes. So it is better not to gamble the money that you can't afford to lose.