Beginning today, treat everyone you meet as if they were going to be dead by midnight. Extend to them all the care, kindness and understanding you can muster, and do it with no thought of any reward. Your life will never be the same again.
-- Og Mandino

Let us always meet each other with smile, for the smile is the beginning of love.
-- Mother Teresa

One of the kindest things you can do for yourself is to be kind to everyone you come in contact with. All of life is a giant feedback loop. When you send out kindness, it gets returned to you several times over. When you take time and care in your interactions with others, you will find others taking tome and care in their interactions with you. Develop a picture in your mind of how you would like to be treated in your ideal world, and then set about making sure that is how you treat each person you come across.