Biggest reason that NATS drives me nuts is that I have to sit around with people who know less about a subject...oops, excuse me, they have probably read more books on the subject, but never been able to take the lessons from those books and put them into practical use.
Last year, judging Musical Theatre, Upper Level High School Men, I had to sit with two of the most unknowledgeable people I could possibly be paired with. These guys couldn't get over themselves with this kid out of Northen VA. Asked why I wasn't enamoured with him, and was with a young tenor I now teach, I stated that "Well, I can't judge him until he gets his tounge off his vocal chords and sings. Plus, everything is the same. Pretty boring."
VANATS is a time that I get to see my Mate Chris Mooney, and we gripe about idiots trying to teach voice. There is being nice, but recognizing crap for what it is: CRAP. And it still sinks to the bottom in the long run.