I certainly know what I used to do: I avoided eye contact and avoided introducing myself, preferring, oddly, to pretend that I already knew the person, which led to confusion on their part and awkwardness all around.
I act like I don't know a person is there when I barely know them and don't know if I should greet them or not. I act like I didn't hear anything when an Uber driver puts me in an awkward spot.
