The etymology of happiness harkens back to a time when the feeling wasn't expected:

Greek mythology, ancient Egypt and cultures throughout the Mediterranean before and after Christ perpetuated the idea that happiness was almost always a miracle. … In English, for instance, the root of happiness comes from the Middle English and Old Norse happ, which meant chance and fortune and shows up in the words “perhaps,” ”happens,” happenstance,” and “haphazard.” In Spanish and Portuguese the words felicidad and felicidade stem from the latin world felix, which means luck, sometimes fate.