The world is so unpredictable. Things happen suddenly, unexpectedly. We want to feel we are in control of our own existence. In some ways we are, in some ways we're not.

The market is a pendulum that forever swings between unsustainable optimism (which makes stocks too expensive) and unjustified pessimism (which makes them too cheap). The intelligent investor is a realist who sells to optimists and buys from pessimists.