Things happen without stopping. Some occurrences generate happiness and joy; some circumstances generate unhappiness and sorrow. That's how we see and think; however, the reality is things happen as they are. They do not want to create happiness or unhappiness. We ourselves generate happiness or sadness according to how we see it. 

In Kassapa Buddha's time, there lived a merchant who was devoted to the Buddha. In the same city, there lived a man who was not happy with that merchant and wanted to make harm to the merchant. Then, he robbed two-three times the merchant's shop and destroyed his palace and garden. He did so many things to harm the merchant, but nothing worked well. Then, that man learned that the merchant was devoted to the Buddha, and if he made any harm to the Buddha's vihar, it would change the merchant's mind. Then he gave fire to the Buddha's kuti while the Buddha was out of it. 

After hearing this incident, the merchant clapped and jumped with joy. It is not because the Buddha's kuti was destroyed, but because he has an opportunity to build another new vihar for the Buddha. Instead of seeing the drawback, he saw the benefit of it. He saw the opportunity. 

This is same with the all happenings that you face today. There are benefits and drawbacks; there are reasons to be sad, and there are reasons to be happy. You see what you want to see. If you want to see the opportunity, you see it. If you want to see the disadvantages, you see it too. Thus, joy is not what is happening, but the joy is how you see it. The choice is yours.