Hunter-gatherer tribes are usually highly egalitarian (at least if you're male)—the all-powerful tribal chieftain is found mostly in agricultural societies, rarely in the ancestral environment. Among most hunter-gatherer tribes, a hunter who brings in a spectacular kill will carefully downplay the accomplishment to avoid envy.
Maybe, if you start out below average, you can improve yourself without daring to pull ahead of the crowd. But sooner or later, if you aim to do the best you can, you will set your aim above the average.
If you can't admit to yourself that you've done better than others—or if you're ashamed of wanting to do better than others—then the median will forever be your concrete wall, the place where you stop moving forward. And what about people who are below average? Do you dare say you intend to do better than them? How prideful of you!
Maybe it's not healthy to pride yourself on doing better than someone else. Personally I've found it to be a useful motivator, despite my principles, and I'll take all the useful motivation I can get. Maybe that kind of competition is a zero-sum game, but then so is Go; it doesn't mean we should abolish that human activity, if people find it fun and it leads somewhere interesting.
But in any case, surely it isn't healthy to be ashamed of doing better.
And besides, life is not graded on a curve. The will to transcendence has no point beyond which it ceases and becomes the will to do worse; and the race that has no finish line also has no gold or silver medals. Just run as fast as you can, without worrying that you might pull ahead of other runners. (But be warned: If you refuse to worry about that possibility, someday you may pull ahead. If you ignore the consequences, they may happen to you.)
Sooner or later, if your path leads true, you will set out to mitigate a flaw that most people have not mitigated. Sooner or later, if your efforts bring forth any fruit, you will find yourself with fewer sins to confess.
Perhaps you will find it the course of wisdom to downplay the accomplishment, even if you succeed. People may forgive a touchdown, but not dancing in the end zone. You will certainly find it quicker, easier, more convenient, to publicly disclaim your worthiness, to pretend that you are just as much a sinner as everyone else. Just so long, of course, as everyone knows it isn't true. It can be fun to proudly display your modesty, so long as everyone knows how very much you have to be modest about.
But do not let that be the endpoint of your journeys. Even if you only whisper it to yourself, whisper it still: Tsuyoku, tsuyoku! Stronger, stronger!
And then set yourself a higher target. That's the true meaning of the realization that you are still flawed (though a little less so). It means always reaching higher, without shame.
Tsuyoku naritai! I'll always run as fast as I can, even if I pull ahead, I'll keep on running; and someone, someday, will surpass me; but even though I fall behind, I'll always run as fast as I can.