The biggest stupidity of gamblers is all-in bets in the desire to win back a loss. In this case, it is impossible to win, because after the next loss, this player will again try to repeat the same thing, and in the end he will still lose everything. There is no need to think that such people have any chances for a positive outcome.
Yeah, having positive mindset is important but having positive mindset in gambling for believing he can recover all of his losses is really a wrong mindset. Every gambler should know and aware if they gamble only for fun, if they can't find the happiness in gambling when they're keep losing, they shouldn't gambling at all. Gambling is a choice and each person has it's own interest, so not all people can become a gambler.
If a person wants to gamble they need to make a fair evaluation of who they are, as I have known a lot of people that are very bad losers and as soon as things do not go their way they begin to do all kind of things which are way out of line for something that is just a recreational game, and if a person like that were to gamble then I have no doubts they will get into deep trouble relatively quickly as they will be unable to accept the fact that casinos will beat them most of the time.