"There are so many different kinds of people in America, with so many different boiling points, that we don't know how to fight with each other. The set piece that shapes and contains quarrels in homogeneous countries does not exist here. The Frenchman is an expert on the precise gradations of espèce de and the Italian knows exactly when to introduce the subject of his other's grave, but no American can be sure how or when another will react, so we zap each other with friendliness to neutralize potentially dangerous situations."