The most common cause of low prices is pessimism - some times pervasive, some times specific to a company or industry. We want to do business in such an environment, not because we like pessimism but because we like the prices it produces. It's optimism that is the enemy of the rational buyer.
The vanishing, volatile froth of the present which any shadow will alter, any thought blow away, any event annihilate, is every moment converted into the adamantine.
History demonstrates that participants in financial markets are susceptible to waves of optimism. Excessive optimism shows the seeds of its own reversal in the form of imbalances that tend to grow over time.
We look for some reward of our endeavors and are disappointed that not success, not happiness, not even peace of conscience, crowns our ineffectual efforts to do well. Our frailties are invincible, our virtues barren; the battle goes sore against us to the going down of the sun.