Happiness is variously associated by different people with a multiplicity of conscious states, such as calm contentment, ecstasy, hilarity, elation, and others. These states all have some claim to be parts or aspects of happiness.... However, they certainly don't all obtain together, and some of them, once again, seem incompatible with each other--ecstasy and calm contentment, for instance.... It may be that happiness is one of those concepts of "folk psychology" that doesn't designate any psychological state, and can't have any explication in terms of the kind of science that tries to discover general laws or regularities.
NICHOLAS P. WHITE, A Brief History of Happiness