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.