@Hogie.Harmonica - I knew I didn’t quite have the right term somehow. I’ve gone back and edited my original title and post to read “productive tension” rather than “creative tension.” The whole point is that while is challenging to hold tension, it will also lead to growth that otherwise wouldn’t be possible.
There also is, of course, also unproductive tension, which @Jay1 gets paid to resolve.
I know you were kinda half-joking there, but I think “personal productive tension” is a fascinating concept as well.
Because we want to challenge ourselves, but at the same time we have to somehow keep ourselves relaxed and playful and having fun.
It’s important to listen to great players.
But the ego is so crazy, it can take us from a place of awe, wonder, and inspiration, over into a place of self-sabatoge (as I talked about in my post The Green Monster of Jealousy.)
And the other interesting thought to note on this subject is that sometimes wanting something too badly introduces tension that sabotages us from achieving it as quickly and effortlessly as we otherwise could, which I think Kenny Werner examines brilliantly in his book Effortless Mastery..
I love your list Peter! And, of course no list of productive tension topics in harmonica would be complete without Tonguing vs Lipping. 
YESSIR! When it comes to practicing, I like the concept that “nothing is wasted.”