When I first read “Market Wizards”, I didn’t quite understand this statement. Now after trading (and mostly losing) for a few years, I can say I finally get what Ed meant.
It’s absolutely true in my case. I realized I actually felt better when losing than winning deep in my heart. After thinking hard about this, it eventually came to me that I had a covert conviction that trading is a bad activity that does no good to the society’s well-being.
My profession is in science and technology and I have done well in my career - published a number of scientific papers and did a few technical inventions, which are all undoubtedly benefiting the society.
Once I figured this out and abandoned that secret conviction, my trading got much better. I told myself I deserved the winnings because I worked hard for it. So it seems to be a psychological phenomenon, but it can be hidden in the sub/unconsciousness and not immediately obvious.