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 should cultivate the optimistic temperament, and endeavour to see the good that dwells in everything. If we sit down and lament over the imperfection of our bodies and our minds, we profit nothing; it is the heroic endeavour to subdue adverse circumstances that carries our spirit upward.
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.
Optimism is a good characteristic, but if carried to an excess, it becomes foolishness. We are prone to speak of the resources of this country as inexhaustible; this is not so.
An optimist will tell you the glass is half-full; the pessimist, half-empty; and the engineer will tell you the glass is twice the size it needs to be.
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.