The the laws of interviewing for jobs.
I think I've figured it out that it goes like this:
If I think I've really nailed a job interview and will get called back for a second interview, I won't.
If I get mulitple job interviews, know the right people, have all the right skills, and am basically perfect for a job, I won't get the job.
But here's the kicker... if I've had a long, tiring day and my brain is completely fried, and I walk out of an interview kicking myself for having been "off," I'll get a call back within the hour for a second interview.
Go figure.