Zen's greatest contribution is to give you an alternative to the serious man. The serious man has made the world, the serious man has made all the religions. He has created all the philosophies, all the cultures, all the moralities; everything that exists around you is a creation of the serious man. Zen has dropped out of the serious world. It has created a world of its own which is very playful, full of laughter, where even great masters behave like children.