The Golden Rule

Love for others what you love for yourself, and hate for others what you hate for yourself. Oppress no one, for you do not like anyone to oppress you. Do good to others just as you would like good to be done to you. Dislike in yourself what you dislike in others. Treat others the same way you want to be treated. Do not speak of what you do not know, for what you know might be little. Do not say to others what you do not like to be said to you.
— Imam Ali

I’m not sure there is a more concise list of rules to follow in order to live a happy, fulfilling life.