(or at least, my personal take on it!)
Over the last couple of months, I've been interviewing candidates for a couple of different roles at Microsoft at a rate of almost one a week. Interviewing is definitely something of a skill, both for the interviewee and for the interviewer. A good interviewer doesn't ask random questions, even if it seems that way - they're trying to get a candidate to reveal enough about their character, skills, temperament and awareness that they can determine whether they'd be a good hire for the team.
I enjoy the mental stimulus of being on either side of the desk for an interview: as an interviewer, the challenge of trying to get through the mask that people sometimes put up to find out where someone's real talents and weaknesses; as an interviewee, the process of finding out more about yourself and the areas where you personally need to develop. Either way, it's a process of continual learning.
One thing that surprises me is how many potential new hires fall into the same "traps". I don't try to catch people out or set trick questions, but I see people who don't do themselves justice in the way they present themselves. Here are a few ways I see people shooting themselves in the foot, based not on any individual candidate but a broad aggregation of the perhaps 15-20 interviews that I've conducted in the last year:
In general terms, it's in both the interviewer and the interviewee's interest to determine whether the person is a "good hire" or a "bad hire". No matter how much you want a job coming into an interview, pretending to be someone you're not (more technical than you really are, more interested in a certain type of work than you really are) to land a position doesn't lead to satisfaction in the long run, when you wind up getting bad performance reviews because your skills just don't mesh with the requirements of a role. On the other hand, if you can find a job that really matches your interests, skills and goals, you'll have great fun doing it and naturally excelling in it.