Positive thinking gives you an edge every time a person is gambling. Base on my experience, every time that you have doubts on your card, no matter how strong it is, you will end up losing the game because you are not confident. Especially in the game of poker, the other player will definitely feel that you are bluffing if you're not confident. You are also willing to take the risk if you are thinking positive, the more you try, the more chances of winning.
I don't know mate, but your positive thinking will not change the outcome of the game. If you are not confident then don't bet on it simple as that.
We all know for a fact that everything is based on luck, and even if you are not that confident but decided to bet and won, what do you think influence the outcome then? Luck or Confidence?
Confidence of winning based on positive thinking is actually the last thing anyone want to do and if they want to go ahead, they may need to go ahead to join some support groups to see how that mentality has landed some people there and trying to find a way to get out of it.
It is one mentality that a lot of people had and at the end of the day, they have become so addicted while trying to win from gambling, keep trying and hoping to win and until they lose everything and all they have left is for them trying to recover with still their positive thinking.