What is the most beautiful emotion?

Every emotion is the most beautiful in its own right, for each emotion carries with it a unique power that it grants the person experiancing it. Happiness is contagious, it spreads across the world infecting people all over. one smile can brighten the day of several hundred people. Sadness you've already explained. Fear can keep a person alive, giving you the energy to fight when cornered, or the stamina to run like hell. It can even give you the strength to save someone who's in dire peril. (example being a mother saving her child) Rage can fill the body with superhuman strength and the ability to ignore pain at the cost of rational thought. There's many more I can get into, but each is unique, so I can't really compare them to eachother