When John Coltrane plays the melody early in the track Harmonique, you can hear some of the notes crack.
Of course, Coltrane was completely capable of playing these notes the traditional way. And yet he didn't.
It's this effort and humanity that touches us about his solo, not just the melody.
Sometimes, "never let them see you sweat," is truly bad advice. The work of an individual who cares often exposes the grit and determination and effort that it takes to be present.
Perfecting your talk, refining your essay and polishing your service until all elements of you disappear might be obvious tactics, but they remove the thing we were looking for: you.