Presidents of the United States have to face different, and more difficult, etiquette challenges than the rest of the Nation's citizens. For instance, shaking hands and smiling during functions for thousands of people, some significant percentage of which are likely to disagree with your policies or person, could wear down even the healthiest of men. (First Ladies could cleverly get out of this by holding a bouquet firmly with both hands, at least back before Eleanor Roosevelt.) An American President with the least robust constitution, however, figured out some good tips for shaking hands with large numbers of people, mainly men who were larger and stronger than he, and eager to prove it. In his diary, Polk revealed his secret: "I told them that I foudn that there was great art in shaking hands, and that I could shake hands during the whole day without suffering any bad effects from it. they were curious to know what this art was. I told them that if a man surrendered his arm to be shaken, by some horizontally, by others perpendicularly, and by others again with a strong grip, he could not fail to suffer severely from it, but that if he would shaked and not be shaken, grip and not be gripped, taking care always to squeeze the hand of his adversary as hard as he squeezed him, that he suffered no inconvenience form it. I told them also that I could generally anticipate when I was to have a stron ggrip, and that when I observed a strong man approaching I generally took advantage of him by being a little quicker than he was and seizing him by the tips of his giners, giving him a hearty shake, and thus preventing him from getting a full grip on me." Read the full account here.