Swami Vivekanand talks about the karma yoga on the topic " We Help our selves, not the World" . He tries to give the very important practical knowledge of the world.
This world is like a dog’s curly tail, and people have been striving to straighten it out for hundreds of years; but when they let it go, it has curled up again. How could it be otherwise? One must first know how to work without attachment, then one will not be a fanatic. When we know that this world is like a dog’s curly tail and will never get straightened.