Just as there are laws of Conservation of Matter and Energy, so there are in fact Laws of Conservation of Pain and Joy. Neither can ever be created or destroyed. But one can be converted into the other.
Spider RobinsonAnd I repeat: if there is anything that can divert the land of my birth from its current stampede into the Stone Age, it is the widespread dissemination of the thoughts and perceptions that Robert Heinlein has been selling as entertainment since 1939.
Spider Robinson