There is some (tenuous) science that maps to the phrases "open" and "closed".
On the days when I feel open, strangers on the street see me, acknowledge me, and tip their metaphorical hats at me.
On the days when I feel closed, people ignore me.
It seems that the vagal nerve being contracted, or relaxed, can be picked up by all people. It is what our unconscious calibrates for.
When that nerve is contracted, our voice boxes too, are constricted. Prompting and immediate "what's wrong?" from friends and sometimes strangers.
This excites me: The knowledge that a nerve being contracted or relaxed has so much information to others. Because this nerve is under my control.