That concept of verbal smiling is interesting; I imagine it is related to how expressive and varied or non-monotone the voice is. I'm probably pretty bad at it.

I tried saying some things with a normal facial expression versus with a (forced) smile, and the former comes out more monotone for me than the latter, but I'm not sure the latter sounds friendlier.

With social smiling, I think I'm neither particularly bad nor good at it. (From my own point of view; don't know if others would agree.) I could write more on the topic, including some things that I didn't see mentioned in that thread. Maybe another time.

I thought the mention of "dude nod" was interesting, as I've noticed myself do that a few times when passing male strangers in the street.