You cannot understand and experience happiness without experiencing sadness. You cannot understand or experience joy without experiencing sorrow. It is the contrasts in life that allow you to see with clarity. Contrasts are important and vital to the total understanding.
Messengers of joy, sorrow, happiness and sadness will greet you. Sit with each, to the best of your ability, in each present moment. Learn from them in those present moments, and know that there will be times when you are unable to do so. When this happens, forgive yourself and move on.