Totally get what you're saying Dante! I will say though, this particular version of Calm that I was experiencing that day was not the same thing as Flow.
I have been able to get to a Flow State in my work just about every day since I started consistently Writing - some days take a bit longer of course, but I always do find Flow.
There was something very different in the feeling of this Calm... It was a bit more pervasive than a Flow State (Flow States typically last between 50 - 90 mins., assuming no distractions), and it didn't necessarily contribute to higher performance per se. "Zen" is a closer word though I'm not exactly sure that is quite right either.
Regardless of the technical word for it, that calm was very fascinating, and it ended up being extremely beneficial later that day with a Coaching Session I had!
Thanks for the kind words Dante!