"Happiness" seems too squishy and vague a word to be of any use. I prefer "satisfaction". I think of it as a kind of geometric mean of happiness, smoothing out

"Happiness" seems too squishy and vague a word to be of any use. I prefer "satisfaction". I think of it as a kind of geometric mean of happiness, smoothing out the extreme ups & downs that "happiness" can be subject to. Not sure it's any easier to translate into an equation but it's certainly easier to reason about.