To me, 'being happy' is a vague, categorical, unfocused term like 'good', 'positive', 'introvert', or 'extrovert'. You can go into specific behaviors and feelings and then it makes a lot more sense.

For example, the author could be 'happy' in most areas of his life, but the choices he made in his life could make his dating life harder (if he's single) and he finds he's less 'happy' in that area.