You've probably seen/read interviews with people where the person doing the interviewing has a list of questions already prepared and just goes through them one by one, occasionally asking a question that was just answered as part of a previous question or failing to dive deeper into an answer that is so fascinating that it's a shame not to explore it more. I find those kinds of interviews frustrating since the interviewer is putting no thought into it.

A good interviewer is someone who asks questions, then connects them with previously learned information in order to ask a better, more insightful question that they otherwise wouldn't have been able to ask had they not just learned the info. It's clear that this interviewer isn't just going down a list of things to ask. A really good interview is one where the interviewee walks away having learned something, even though they've only answered questions posed to them.

Asking questions is a lot like this. If you're more like the first interviewer going through a list of disjoint questions (or questions which only probe for further detail) then it's not surprising to me if people get annoyed. If you're like the second interviewer asking insightful, deeper questions where you're connecting the dots in such a way that you're asking questions that matter and they still get annoyed then perhaps it's just them. Of course, if it's totally new territory for you then you may need to go through seemingly disjoint questions in order to establish a baseline of knowledge to be able to ask more intelligent, interesting questions. You may lose people in your attempt to bootstrap your knowledge to that level.

It's also entirely possible that they hate their job but through cognitive dissonance they've learned to cope with it. Your questions may increase the dissonance for the work they do in which case they'd rather avoid thinking about it entirely.

Relevant XKCD: http://xkcd.com/1053/

- randall