Happiness...What constitutes it!

Sometimes I wonder...
What makes a person happy, why do a person become happy, when does he become happy, what are the things that make him happy. Or in other words, metaphorically, a scientist would say what is the formula for happiness; a manager would ask what are the resources needed to achieve happiness, a doctor would enquire what are the symptoms of happiness or an accountant would say how to open the account of happiness. But the final question remains the same i.e. "What constitutes happiness?".

There is no definite answer to this question and 'n' number of pages can be written on this topic. But if it is a question then there should be some answer to this, as every question has an answer. Therefore I tried to discover the answer to this question.
I have seen people becoming happy when they go for shopping, people become happy when they party, people become happy when they get gifts, etc. There can be infinite number of things which make people happy. In a nutshell I would say that people become happy when they want something and that want is fulfilled.
But, what if a person wants something and he gets it straight away, without any struggle, without any hard-work, without facing much difficulties, without facing any competition and without putting-in his full efforts. Yes, this is the point when a person becomes happy but that happiness is not complete. It is incomplete as the person got, what he desired, so easily that he cannot even realise that he has got it. So, a person may not be happy even if he has got something that he wanted.
Therefore, the final reason for the happiness of a person is not the fulfillment of his wants, it is rather something else. It is 'Satisfaction'. When a person is searching for happiness, this means that he is searching for satisfaction. If a person is satisfied with what he has or what he gets, he will be happy. Therefore satisfaction is one of the key elements of happiness.
In other words, I would say that happiness is not an external phenomenon, it comes from within the person himself. It is his perception of 'satisfaction' that makes him happy or sad.

Someone has rightly said:
"Happiness is like a butterfly; the more you chase it, the more it will elude you, but if you turn attention to other things it will come and sit softly on your shoulder".