In case you haven't seen it yet, Russell Roberts and William Polley have a discussion of "what the public doesn't know about economics" in the latest edition of the Wall Street Journal's Econoblog feature. On this topic, I have lately had the opportunity to interview a number of economists about various things, as part of an exhibit that is being developed for a soon-to-be-finished learning center at the Federal Reserve Bank of Cleveland. I generally ask different questions of different people, but try to ask this one of everyone: If there was one lesson from economics that you could magically implant into the brain of everyone, what would it be?
You'll be able to see these answers yourself in the near future, but my answer would be this: Trade is good.
Whether your an "official" economist or not, feel free to leave your own opinion in the comment section.