I think this hits it precisely. One thing I'd like to add: > if he expresses a little impatience or frustration... IMO what sets Feynman off at the beginning

I think this hits it precisely. One thing I'd like to add: > if he expresses a little impatience or frustration... IMO what sets Feynman off at the beginning is the way the Interviewer asks his question by describing his feeling when interacting with magnets. I can almost hear him think - "oh god, now it isn't only the magnetism that I should explain, but even this guy's feelings - am I a neuroscientist?" Physicists are trained to be precise with language, so asking about feelings when just trying to know how magnets act may be understandable to the common (wo)man, but people like Feynman stop being a common man when talking about physics. As soon as the interviewer rephrased it to the how question, his mood turned and something in there got unlocked. To me this is beautiful to watch.