I can think of only a few rituals that encase my body with adrenaline and sweat: running a race, struggling through Bikram yoga, having that dream where I'm still in junior high and I've completely forgotten about a huge project that's due in less than an hour, and interviewing for a job.
A job interview is the perfect storm of anxiety for most job seekers. You're put through a battery of questions. You're expected to exude all of your good qualities without revealing your bad ones. You also need to get a feel for the company. Oh, and try to keep your nerves to a minimum -- a jittery candidate could suggest someone hiding something or not qualified for the job.
Basically, interviews are like first dates with a bigger impact for your W-2s.
Few job seekers walk into an interview without a considerable amount of anxiety in their bellies. While you can't get rid of it all, you can learn how to control it so that you can give your best interview and get the job.