It is possible that a scientific discovery will be made that humans will later regret because it has awful consequences. The problem is, we probably would not know in advance and, once the discovery is made, it cannot be undiscovered.
The really frightening thing about middle age is the knowledge that you'll grow out of it.
The average trade of an individual is in the thousands of shares, whereas the institutional trade can be in the millions of shares. Clearly, the bigger the order, the bigger the move in the stock.