Happiness is something everyone wants to have. One may be successful and have a lot of money, but without happiness it will be meaningless. We don't need ‘stuff’ to be happy because happiness is a state of mind, a feeling, something inherent to the person, but if the goal of one's life is becoming rich, that person might just feel unhappy until his/her goal is achieved.
According to Dictionary.com the definition of happiness is:
1. the quality or state of being happy.
2. good fortune; pleasure; contentment; joy.
Or you can check out the way I define happiness.
However, happiness is a fuzzy concept and it is difficult for people to agree on the same definition. No matter what research tells us, people always had and will have their own definition of happiness generally shaped by what they don't have and not by what they have. While always wanting to go a bit further is the engine of progress, always feeling unhappy because of the missing ingredient doesn't seem to be the best option for living a good life.
Here’s a cool video asking people about their definition of happiness. Alternatively you can check out my collection of happiness quotes to read a variety of beliefs writers and philosophers have about happiness. And last but not least, how do YOU define happiness?