It's easy to learn all the notes that make good music and all the rules that make good business, but a fellow's got to add the fine curves to them himself if he wants to do anything more than beat the bass-drum all his life. Some men think that rules should be made of cast iron; I believe that they should be made of rubber, so that they can be stretched to fit any particular case and then spring back into shape again. The really important part of a rule is the exception to it.
