One thing to notice is that most competitive sports are "zero sum games", meaning that the winner gets a +1, and the loser, -1 making the sum:
(+1) + (-1) = 0

Another thing that also stops a lot people is self-doubt, usually stemming from the invalidations of others. What I've realized recently is that for these bad thoughts to have any force, I have to 'ay-out' attention to both the invalidating thought and myself as it's victim. Thought and thinker. Internalized, it's like having two cats in a sack causing all these bad feelings, without ever before understanding that I expended my own mental energy making-up, or mocking up, both cats by giving them my attentions at all, by taking any of it seriously.

With me it was like being almost constantly, psychologically hand slapped, retraumatized by the same thoughts, while being completely unconscious of the fact that they were both my own hands that were causing all the self-inflicted pain and doubt. By making some time to still these negative thoughts, I've gained a great deal of s(S)elf-assertiveness and insight myself, and enormous relief.

Do you think it might be true that a lot of chronic anxiety and melancholy might have the psychological dynamics of a zero-sum game, ones that are unhealthful for anyone to even start? I don't think many people grok this very well, but I think quite a few others do a kind of stilling/centering thought-exercise almost automatically.

I've actually had this kind of dialogue with associates that are upset, confused; it was very uplifting for them.
Hope this helps.

"What is the sound of one hand?"

sincerely,