A king may be a tool, a thing of straw; but if he serves to frighten our enemies, and secure our property, it is well enough; a scarecrow is a thing of straw, but it protects the corn.
The end and aim of spying in all its five varieties is knowledge of the enemy; and this knowledge can only be derived, in the first instance, from the converted spy. Hence it is essential that the converted spy be treated with the utmost liberality.
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.
When, however, you have an enemy, then do not requite him good for evil: for that would shame him. Instead, prove that he did some good for you. And rather be angry than put to shame! And when you are cursed, I do not like it that you want to bless. Rather curse a little also! And if you are done a great injustice, then quickly add five small ones. Hideous to behold is he who is obsessed with an injustice.