Being incredulous that others don't understand

Don't.

Can you expect people you talk to, to have the same vocabulary, knowledge, and worldview as you? Probably not. Should you explain everything like they're a child? Probably not. Should you act incredulous when they don't understand what you're saying, even if it's super obvious? Nope!

A better way to react is to hide the fact that you're surprised, and instead either move on or explain the concept.

Some of my interactions that I regret the most have been my acting incredulous. For instance, when I said "here's an easy question" and they couldn't answer it. Or when I showed how sure I was that my counterparts in dialog knew a particular word and they didn't.

As always, there's an xkcd comic succinctly describing the issue at hand.