To start with... the conception of happiness is immanent to the culture that generates it, so we cannot speak of one happiness, but one general conceptualization of something that generally is not properly defined. For us it might (or not) be money, while for the heroes of Homer was receiving kudos.
On the other hand, isn't it a border that is constantly moving? Is happiness at all possible? As a matter of fact... what is happiness? Tell me, try to obtain it and you'll see it is not what you thought it was.