Despite being a prof in Computer Science, publishing papers, etc., I used to meet people all the time that just amazed me. Keeps you humble.
E.g., Volker Strassen, the matrix algorithm guy, sat in on a seminar I was presenting on my research when I was a grad student. Despite being on a topic completely unrelated to anything he ever worked on, he was one slide ahead of me. That is, I was talking about something, he would point a problem with that, and of course that was what my next slide is about. He just kept doing that.
Sort of annoying to be interrupted like that. (I just wanted to say “Hey, just wait a slide and then ask a question.”) But also amazing he was figuring this stuff out in real time.
Furthermore, most of these people are fairly nice and friendly. Not at all the usual stereotype.