Some folks are harder to read than others. Maybe their whole family behaved that way; everyone emoting openly and spontaneously without hesitation or shame.
Then a family next door places more value on appearing strong, steady and stoic. They learn to keep a placid, neutral expression on their face and in their voice.
Someone may have grown up with a violent alcoholic as a parent, and does not want this parent to know that they’ve touched a nerve, as this may only lead to more harrassment.
“...everyone emoting openly and spontaneously without hesitation or shame.
...[Others] learn to keep a placid, neutral expression on their face and in their voice.”
Sounds like my wife and me.
I worked with a guy from South Africa & I was in a meeting with him and a lady and he was giving her negative feedback and I could see her getting more & more emotional & the guy from SA had no idea he was upsetting her until she started crying. Most unemotional, cold person I had ever met.