Success is relative. It is what we can make of the mess we have made of things. 
To travel hopefully is a better thing than to arrive, and the true success is to labor.
I believe that the very purpose of life is to be happy. From the very core of our being, we desire contentment. In my own limited experience I have found that the more we care for the happiness of others, the greater is our own sense of well-being. Cultivating a close, warmhearted feeling for others automatically puts the mind at ease. It helps remove whatever fears or insecurities we may have and gives us the strength to cope with any obstacles we encounter. It is the principal source of success in life. Since we are not solely material creatures, it is a mistake to place all our hopes for happiness on external development alone. The key is to develop inner peace.
