The richest person is the one with a cool mind, free of tension and anxiety. Changing all these world situations is not in our hands. We are not going to stop all these things. But what is in our hands is the ability to find joy and peace right here and now. If we live in the present, even thought he whole world might blow up in a minute, it won't bother us. We can be happy in situations of tension. If we have decided to be happy, nobody can make us unhappy.
-Sri Swami Satchidananda, The Yoga Sutras of Patanjali