Whenever I meet someone whose world-view is really different from mine, I tend to think of this book. You know, they still believe that Saddam was behind 9/11 and hid his nukes in Syria, or Al Gore made up global warming for political reasons, or the Grand Canyon was formed a few thousand years ago during Noah's flood... that kind of thing. Read it and you'll see why. It's fun!
Next time you come across one of these people, they'll notice you're smiling rather than snarling, and probably they'll be relieved. You'll spread a lot of happiness. Unless you're foolish enough to tell them what you're smiling about.
PS If you're a PKD fan, check out my Quiz question: http://www.goodreads.com/trivia/details/30131-Who-is-Chipdip-K-Kill-