> The best candidates light up when they have a chance to explain something cool, no matter who is listening and get even more excited when you ask a question about a detail.

I agree this is true in a general human-conversation sense: many good engineers like discussing things with non-engineers if the latter show any interest, and the best can actually explain things in understandable ways. But I think in the context of Corporate Bureaucracy things can be a bit different: I can forgive somebody who's normally a patient explainer being frustrated if they feel their time is being wasted by endless HR bureaucracy. In particular, there's a difference between someone asking you about a detail because they're actually interested in it, and someone asking about it even though they don't care at all, because it's on a checklist and their job is to plow through the checklist.

Of course, that still wouldn't justify being a condescending ass, and certainly wouldn't justify giving wrong answers! If I felt the other person was uninterested and operating by rote, I would probably just recite correct, by-the-book answers.