Is pretty obvious that having a positive mindset when playing gambling would never in any way guarantee you winnings easily, rather it will still result to more losses at the end of day. However, one might have a positive mindset in other areas, but sincerely speaking gambling doesn't work with any positive mindset, unless the luck is on your side. If not there is nothing like being positive in gambling.
Personally, a positive attitude has never helped me in gambling. There was no positive result at all. Yes, it is nice to play when you are calm and nothing is bothering you. It even slightly improves the overall atmosphere of the process, but nothing more.
There are many other areas of human life where positive emotions help in business, but definitely not here. This is a big misconception. Therefore, there is no point in immersing yourself in this world of illusions.