Can’t see it. Masks.
Depends on what type of smile it was…
Depends on the smile. There’s a difference between “I hope you have a good day!” and a lecherous smile. I know because I’ve had to learn to tell the difference since I was 8.
I normally just head nod
I usually don’t make eye contact with people walking by (unless they have a dog and then I only look at the dog) but if by chance it happens then I smile back.