Via a comment on some blog :

“Trading isn’t about profit and loss. It’s about self-actualization. There are many ways to fulfill your potential. We happen to choose trading. And that’s not a small thing. Success and failure in this arena is beyond our control, and what’s more, it can be objectively measured, and I think that is why trading failures cause so much cognitive dissonance. We suffer so much when we lose not because we can’t handle being wrong, but because every defeat moves us one step farther away from self-actualization.

There are many pursuits that don’t offer this obstacle. If you want to become well-read, for instance, all you have to do is read, and with every book you read, you are more well-read than you were before. Not so with trading. All of the hard work might amount to nothing. Who knows? Being able to handle this uncertainty is perhaps the most important part of the process. And to me, it’s the thing that makes our pursuit worthwhile.”