The truth about happiness is that God wins in the end. He has defeated Satan through the resurrection and therefore we should live happily ever after. So next time the nieve, bubbly college freshmen approaches you with how wonderful life is because this boy she just met shares all the same likes as her, try not to dash her hopes and speak "too much" reality into her gum drop world. And when the high school senior guy shares his determination that God has gifted him to play pro football, be gentle and supportive. Happiness is a great thing, maybe one of the best of things.
God is an agent of Happiness and joy. The truth is that with either won the same ending is true; We Win! Death has been conquered! The grave has no power! Satan is fighting little battles only to already know that defeat is the outcome of his war. In this vein we all receive a happy ending!