Interviews are like therapy. When you get in that room, a person you know nothing about, and who knows nothing about you, asks you questions for 45 minutes to an hour, and basically just listens to you talk. While you go on and on about yourself, the interviewer tries to read between the lines to get clues about the "real you." But instead of trying to diagnose you, or fix your problems, an interviewer, unlike a therapist, tries to determine whether or not your personality and your experience would make you a good match for the position they're trying to fill.
And afterwards, the person being interviewed learns something about his/herself. And feels relieved. And exhausted. And like he/she has accomplished something. Then getting the job, like getting "cured," may or may not happen. But one finds out with time.