Let me clarify, also, that this feeling of improvisation is not limited to music. The sentiment extends well into every day life.
For example, you're on a crowded train. You see something very subtly hilarious happen right in front of you (I wish I could think of a specific example). No one seems to notice, except you look across and make eye contact with a complete stranger that has seen the exact same thing. Quick pause = moment of realization. Then you both burst into laughter.
That's just a little thing; the unexpected caramel chew that your friend produces from their pocket on a walk to the park. Even so, don't you feel a pulse of dopamine when it happens?
Anyway, the improvisations in life are many, but the shared improvisations are the ones that satisfy. Someone to share the miracle with. And here's what's really interesting: as momentary as the example I gave, there are improvs equally lengthy. That go here, go there, go where... and from the inside it looks nebulous, but if you're clever and curious, you get to see what serendipity is all about.
Here we go, Day 196: https://ia700809.us.archive.org/23/items/Improv22612/20120226190641.mp3