Many of Mario Puzo's quotes have been adopted by the American society as clichés.
The following are just a few out of those many:
Great men are not born great, they grow great
Never hate your enemies It affects your judgment
Revenge is a dish that tastes best when served cold
A friend should always underestimate your virtues and an enemy overestimate your faults
A man who doesn't spend time with his family can never be a real man
Never get angry Never make a threat Reason with people
Keep your friends close, but your enemies closer
Falling in love is great but being in love is a disaster
I have always believed helping your fellow man is profitable in every sense, personally and bottom line
The only wealth in this world is children, more than all the money, power on earth
Friendship and money: oil and water