"Only once one has known real sadness can one feel true happiness."

                           This is a motivating statement. I believe that true happiness can only be felt when one experiences the sadness in his life. Human life is a reality Happiness and sadness are the integral and extreme emotions of life and oppose each other and only one either happiness or sadness will effect at a moment. Only one experienced the real sadness can understand the true happiness.
                        There has to be a balance in life. No one can be perfectly happy without experiencing sadness. It is said that "Failure is a stepping stone of success" To analyze this, with repeating failures will lead us to success. Is that so?
              The problem of the measurement of the volume of object when solved by Archimedes gave us the idea of the relativity involved in both happiness and sadness. He ran on the roads shouting "Eureka..." to show the solution to his king.
                        The invention of bulb by Thomas Edison, during the process of inventing a bulb, Edison had to face failures many times. He said to the world that "These are not materials used in the invention of the bulb” after every failure. When he invented the bulb, the happiness he felt was immeasurable. Today millions of people are using bulb remembering Thomas Edison 

                      

It is true that only after one has known real sadness can  feel true happiness.