Interviews are scary as hell. You can't make one mistake and every word you say is up for scrutiny.
I once went to what I thought was an interview. It turns out the guy is not offering me a job. No, he's trying to sell me a job. Basically, he asked me if I wanted to attend several courses that cost $200, and after that, I'd get the job.
Its good I didn't have a credit card at the moment, or he would have sucked me in.