Perfectly put (again)

By the wonderful Dr Sowell.

Many people are so preoccupied with the notion that their own knowledge exceeds the average knowledge of millions of other people that they overlook the more important fact that their knowledge is not even one-tenth of the total knowledge of those millions. That is the crucial fallacy behind the repeated failures of central planning and other forms of social engineering which concentrate power in the hands of people with less knowledge and more presumption.