The word happiness has a fascinating etymology. Its root, hap-, appears in such words as perhaps and haply, but principally in happen. In some peculiar way, therefore, happiness has been seen as having something to do with the way things happen—or to give the matter its more usual name, with luck.
The English language seems to me to be on to something here. Specifically, it is on to the home truth that we cannot, in any ordinary sense, arrange for happiness; rather, happiness must somehow befall us. This truth is evidenced in many ways, but perhaps most accessible is the old wisecrack, “The Constitution may guarantee your right to the pursuit of happiness but it doesn’t guarantee you’ll catch up with it.”