From an experiential subjective point of view,
Happiness is Intentional.
Intentional because you don't have to work for melancholia, it welcomes itself,
Intentional because every other thing in the world can easily make you sad,
Intentional because, you have to strive to maintain it.
I'm from reading a journal I kept 3 years ago ( I don't even know how it survived the fire this long)...
I WAS SAD, I...