Joy in the Merely Real
If dragons were common, and you could look at one in the zoo - but zebras were a rare legendary creature that had finally been decided to be mythical - then there's a certain sort of person who would ignore dragons, who would never bother to look at dragons, and chase after rumors of zebras. The grass is always greener on the other side of reality.
Which is rather setting ourselves up for eternal disappointment, eh? If we cannot take joy in the merely real, our lives shall be empty indeed.