Cops freak me out too - it's so irrational I know. I've got nothing to hide but i feel like I'm in the principal's office or something lol
My first one actually went really well! But this year alone I've done over 100 of them and no matter how many I do there are some that just go completely pear shaped!
My first one was over the phone (he was in Townsville) and I asked him how old he was. He said 'you can't ask a lady her age!' and I said "well you're no lady so give it up!" he was fantastic.
The worst one I ever had was actually about 2 months ago. It was with a senior executive and I had been very clear that I would be interviewing him and he said he understood but when we sat down he flipped the tables on me and interrogated me over the validity of the project! I kept trying to terminate the interview and refer him to my senior managers (ie the people who could answer his questions) but he wouldn't listen- he wanted someone to have a go at and it was me! I had to sit there and take it and it was a write off. It just happens sometimes unfortunately. It's never about you.
I've put my foot in it a few times- I was interviewing business owners once and one was in an industry that I thought sounded really cool and said so but it turned out that business was down and they weren't too impressed!
The hardest part I think -and I think I've figured it out- is when you ask a question and they think that you should know the answer. For example, I was recently interviewing people with a technical background and one mentioned a system/tool that I had never heard of and I was like "oh what do you use that for?" and they were like "you don't know and you're working on THIS project!??". That can be hard because sometimes you lose credibility but I deal with it by acknowledging my ignorance and asking them to help me learn and they're usually really good.
Yes they are just people- I've interviewed a lot of different types of people and most of the time they are normal.
Be flexible - there was one i just couldn't lock down into a meeting time and he was a crucial piece of the next stage. He rang me up one day and said "I'm free now" so we ran through the interview then and there. That sort of thing happens a lot.
Questions: I always go in with 5 maybe six general starting point questions and dig in based on how they respond. And if they don't respond I usually have back up questions up my sleeve or something I can show them to get them talking.
Notes: Write down what you hear not what you think you hear. Don't try to analyze or paraphrase it during the interview. Be careful about what you do write down- they do say things that they might not tell their boss or your boss. They tell stories that they probably shouldn't but I love it because it means they trust you enough to open up- just don't write it all down. Write for the world to see! There was an incident where I was working with people who are not UXers and they wanted to put my notes on a shared access site and show them to people and thought I was crazy when I said no! They did not believe that users would open up to me and tell me things that they wouldn't freely say in general conversation- but they do. The notes ended up being stored in a limited access library that only myself and two others could access and I refused to write names on them other than “Interview 1” etc. Protect the integrity of your research.