i know of a few times that i showed surprise finding out that somebody never heard about something.
this surprise was however never about the other person, but about myself.
i realized, that my worldview was so skewed about some topics, that i believed them to be almost universally accepted. the topics themselves were often unknown to people outside of my online-bubble.
I agree with this in theory, but you are talking about stuff that is a required part of all {4,5,6}th grade science curriculums in the US, and the equivalent in other countries.
I was not feigning surprise, I am literally surprised that this was not realized
this surprise was however never about the other person, but about myself. i realized, that my worldview was so skewed about some topics, that i believed them to be almost universally accepted. the topics themselves were often unknown to people outside of my online-bubble.