Common sayings seem to be the grass roots of the English and American culture. USA is a melting pot of many cultures, so the proverbs included in this app represent years of generations handing them down one to another (mostly orally) with their own cultural spin. Many were told to help educate and pass wisdom down from young to old. Their motive was to teach you a message of behavior or to give you philosophical wisdom. Some come from the bible, although are not actually word for word.
Proverbs and sayings are usually short and sweet or short and tangy. They have been defined as the wisdom of many and the wit of one.