do not start yourself at a deficit
This speaks more to not having a bad attitude or a dismissive attitude when it comes to owning up to yourself.
Part of game is skill, the other part is the belief that you'll be able to achieve anything you set your mind to.
A common example in billiards is the advice to "play with confidence, even if you have no reason to." There's the inherent assumption that something that means "fake it till you make it", but the subtle difference is that in the former, there isn't any faking. It's a positive spin. You're playing with confidence. You're playing at the peak of what you know, even though you understand the vastness of what you don't know.
Playing in this manner means you're always pushing the boundaries, you're pushing right up to the boundary and limits of your own knowledge. Your attitude and confidence develops right next to your knowledge, so over time, you become incredibly proficient.
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