Bubbles on the brain:
"Paul Samuelson once quipped, "Economists have successfully predicted nine of the last five recessions."
"The cost of hiding from a nonexistent giant man-eating saber-tooth tiger is low, but the cost of not hiding from a real giant man-eating saber-tooth tiger is quite high. So hiding more often than there are tigers makes a lot of sense, if you're a caveman.
But as with other habits ingrained into us by evolution, the habit of predicting doom and gloom when it isn't in fact right around the corner might no longer make sense."