I found this cool little ditty about interviewing that frames it as a guided conversation. Totally. Part of what made those interviews with my friend so great (and fun and insightful), apart from the fact that this friend is articulate, thoughtful and totally interesting, is that we already had rapport and she had some trust in me, so we got right to the conversation part - the "center of the onion" - without needing to spend time building a relationship. But that building part is fun, too, if a little awkward at times. I like to think that interviews help "subjects" (if you can call them that) get more insight, and so benefits them, so that it's not a one-way street.
Anyway, here's what some of the link says (emphasis mine):
So, because of that, I only really interview in the strict sense of the word when I have to. I try to do everything else that I can to make sources feel comfortable enough to talk with me. That doesn’t mean that I don’t ask questions. It means I ask lots of questions. But what I mainly try to do is to be a great audience. I egg them on; I nod; I look straight into their eyes; I laugh at their jokes, whether I think they’re funny or not; I get serious when they’re serious. I kind of echo whatever emotion they seem to be sending to me. I do whatever it takes to get them talking.