Happiness and sadness are relative states of the human condition. Our meter moves according to experiential situations. Think about what makes you happy or sad today. Now picture being confronted with a really great challenge. How will the scales change? Often, we need the difficult and dark times to put things back into proper perspective.
Victory over challenges will teach you something about yourself. You will learn that you are much more than a prisioner of circumstance You are the keeper of your attitude. No matter the situation or outcome, you control your outlook. It will drive your reality.