Happiness is that feeling that comes over you when you know life is good and you can't help but smile. It's the opposite of sadness. Happiness is a sense of well-being, joy, or contentment. When people are successful, or safe, or lucky, they feel happiness.
Happiness can be subjective and objective. It depends on how situation we faced and went through. It is subjective because it's in individual mind. It also can be objective if there are authorities on happiness, to me that means happiness is objective when it exists.
But then, I want to believe that happiness is subjective so I can be fair with everyone. First, it is because of the nature of happiness. Happiness is blurry concept at best and have different perception on different people. There is no two people on earth share exactly physical, spiritual, mental and thought at the same time. The simple reason like living in different circumstance, within varied cultures and religions make us dissimilar.
Next, our egos differ significantly and each person will have a unique view of and journey towards happiness. Ego is the conscious mind and the sum total of what we believe of ourselves. People who have a big ego tend to feel less happy because they always think negatively. I believe that when someone is described as having a big ego, this is actually a weak ego. That means the person is weak internally and their identity feels threatened. Thus they need to keep trying to make the outside world match their internal view and it is hard to do.
Lastly, it is subjective because life happens! Every so often life will happen and our circumstances will change dramatically, sometimes for the worst. It is therefore understandable that people will differ in their thinking and disposition, that each person will have his/her own challenges to overcome.