In 1736 Benjamin Franklin was chosen clerk of the Pennsylvania General Assembly. The next year, when he stood again, a new member made a long speech against him, to favor another candidate. Franklin did not try to win the man over with flattery. He heard that the man owned “a certain very scarce & curious Book.” He wrote him a note and asked to borrow it.
The man sent the book at once. Franklin returned it about a week later with a note of thanks. The man then spoke to him for the first time. They stayed friends until the man died. In his Autobiography, Franklin explains it with a maxim: “He that has once done you a kindness will be more ready to do you another than he whom you yourself have obliged.”