I've done lots of them, diligently prepared and have done mock interviews with friends. However, the failure rate is extremely high in my case because they'll ask one question I didn't anticipate and that's it, boom, job gone. Imagine in an exam, you come across one question that you might not have the answer to, you'd still pass or even get a high mark, not so with interviews, they are awful experiences because you're dealing with a minefield, one wrong step and you're done.
I've always been a misfit and have never been accepted by any group, I think interviews are an extension of that. When talking to friends and family I realise, I'm not that bad and am just as good as anyone else, interviews are the inverse, a constant reminder of one's inadequacy and inferiority but they're false and completely scripted. I've found that I've passed interviews where the interviewer does not stick to a procedural box ticking script, but the majority of interviewers are box tickers unfortunately.