I thought of the perfect analogy for playing out. We've been discussing outside playing regularly in my jazz grad seminar this semester, as the required supplementary reading was Dave Liebman's A Chromatic Approach to Jazz Harmony and Melody. The challenge is always to find ways of weaving your lines in and out of the changes with intent and conviction. When I play a run that strays from the changes, it's usually to target a specific consonant, restful moment coming up. Sometimes I like what I did, sometimes not, but I usually don't know what I'm doing during that brief outside section. I just use my ear and intuition and try to play notes that I know won't work under conventional theory.
So here's the perfect analogy that popped into my head one day. Think of the level of control one has when throwing darts. A beginner can probably choose whether to hit inside or outside the board, but without much consistent control beyond that. An intermediate thrower can hit specific regions deliberately and can choose how far outside the board to hit. An expert can throw a dozen darts into a smiley face right on the edge of the board, some inside, some outside. That's what we're trying to do in music. We're trying to superimpose a different kind of structure over the existing harmony, whether it's a sequenced motif, substituted chords, a memorable quote, etc. And just like the expert dart thrower, it requires an extraordinary amount of accuracy (and precision, if you're into that).