"No discussion of the interrelation of stock prices and business conditions would be complete without emphasizing that in the clash of speculative forces on the exchange, the emotions play a part which is not paralleled in the normal process of commerce and industry. The golden mean is non-existent on the Wall-Street, because the speculative mechanism does all things to excess; even the reactions from the heights of fantasy and from the depths of despair are accompanied by convulsions which are distinct from the calmer tenor of business. Those who seek to relate stock movements to the current statistics of business, or who ignore the strongly imaginative taint of stock operations, or who overlook the technical basis of advances and declines, must meet with disaster, because their judgment is based upon the humdrum dimensions of fact and figure in a game which is actually played in a third dimension of emotions and a fourth dimension of dreams."
(Ten Years of Wall Street: Barnie F. Winkelman - as quoted by Barton Biggs in his book ‘Hedgehogging’.)
