If you're lucky and work hard, you can be in the top 10%, 5% or even 1% of a few areas. But even then, you can beat yourself up about not being the best--because even if you sometimes are the best at something, sometimes you aren't. You can always make yourself miserable, if you choose to.
So what do you do? You have 3 choices:
1. sit there and complain about it
2. Deny the reality of your "behindness", which makes for weak men and women (and I didn't raise wimps)
3. Or, you can realize that there's a set of skills related to managing your internal state
The best way to do this is to focus on process-oriented goals, rather than results oriented goals. In other words, take pride in your work not in the output. You can lose every game, yet feel okay, if you set your goals to be play a bit better than last time--and do it.
Once you get there, you can admit others are better than you and be thankful for the opportunity to learn from them--since you're no longer competing.
This is what is meant by "losers focus on the winners, and winners focus on themselves".
It's simple, but not easy. It takes work to achieve this, just like it takes work to achieve any useful skill. And just like any other skill, you'll get this right sometimes and screw it up at others. Just try to do it better today than you did yesterday, yes, like it's any other skill.
Good luck, I'll always be rooting for you.