Nothing lasts forever, same goes with happiness also. Happiness can be found in all those things which are not part of our life, for eg. by seeing children playing and observing them minutely, by cuddling street animals, and by not expecting. Unhappiness arises where expectation starts. True happiness and bliss is where our near and dear ones are not involved, according to me.
Happiness to me is a free state of mind, beyond reasons. There should not be always reasons to stay happy. Happiness should be practiced more than depending upon circumstances. I want to stay happy and I will practice it, even during hard times. It's very tough, but I will!!