That sucks that you had such a bad experience. I'm interviewing for residency myself, and I sat down ahead of time and considered my answers to possible questions, and even wrote them out ahead of time. I think it's a good idea to do this, even though you may not ever get to show off your well-thought out answers. Typical questions are about your strengths, weaknesses, times when you've let yourself down, things you've done that you've been proud of, times when you have shown leadership or creativity, what you would change about your current institution, anything you would like to change about yourself.... etc.
The key to preparing your answers is to turn the negative questions into positive things, and don't EVER, EVER say anything negative about anyone or anything else. Example 1: one of my weaknesses is that I work too hard, and sometimes don't take enough time for myself because I tend to get involved in too many activities. If you say it sincerely, and you have some sort of reasonable context to put it in, like you're not coming off a 5-month vacation-tour of Europe, your interviewer will eat it right up. Example 2: One thing I would change about my current job is that I would give myself more responsibility, because even though I'm new there, I've seen a few ways that they could improve their current system (be sure to be able to back this up). Example 3: One way that I let myself down was that I shed a tear in front of a patient when I told him he had metastatic cancer.
For one med school interview, I was asked (at the end of a very good interview I thought), "So, it sounds like your life has been pretty good. Has anything BAD ever happened to you?" He caught me WAY off guard, and I didn't really feel much like getting into negative, sad things with this stranger. I honestly don't recall what I said, but I pretty much balked. Reflecting on it, I guess I could have turned it to my advantage (and I know my answer for it if it's ever asked in the future).
Finally, always remember that all interviews are two-way, and you are evaluating them as much as they are evaluating you. Feel free to remind them of this -- in a tactful way of course. Example: Q, What do you have to offer this school? A, My enthusiasm and energy, my ability to lead and to see projects through to the end. What sorts of opportunities are available for people like me at your institution?
It may sound cheeseball in writing, but believe me, when you look someone in the eye and say it with a straight face, you make a big impresssion. You should always be your own best advocate, and you can do it all humbly, without seeming like a jerk. Sincerity it key.
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