Years before I met him, when I was 12 years old and reading his books about monsters, John A. Keel taught me the lesson that I had no choice but to be agnostic. If I were not agnostic but remained interested in the kinds of things Keel wrote about, I would end up insane and possibly leading a lunatic cult. The only way to make sure you're sane is to never start BELIEVING any theories. View it all as percentage-chance of reality and play it like poker or baseball-- either playing the odds or going with a gut instinct. Keep reassessing the evidence to see what the CURRENT chances of the various theories being "true" might be.
Since then, I've been thrust into situations dealing with many spooky-weird individuals. One thing I've learned is that anyone who starts telling you that you're paranoid is trying to get you to let your guard down so they can trick you. As long as you maintain strict agnosticism, then this is a 100% reliable prediction.
So Keel's revelation to me at the age of 12 is probably the most important lesson I learned up to that point, and one of the most important lessons I ever could possibly learn.
Belief is a half-step toward insanity.
I hereby present the first Peter's Choice Award to John A. Keel.