Despite having a top 1 % tier of most "good" stats: HDI, Compassion, Inclusiveness, Security, Employment, etc and living in a ecotechno utopia ... my level of Cheerfulness is catastrophically on the red zone of the low 99 % of stats. The single most glaring defect of Aigania.
So it is either a Hedonic Adaptation (not likely by the game) or some other reason. I have seen suggestions of being tied to the tax rate (something reasonable), but utopias are not cheap (having top of the line, bodies, minds and environment (social, economic, and ecological don't come in discount).
I tried to lowered it ... And destroyed the economy and the crime rate went through the roof. I had to spent a year trying to repair the damage and it wasn't pretty.
So, I am stuck in a terminal/peak state. Any brusque change of direction will be fatal.
(And no, I will discard that they are simply stoic or robotic because Rudeness stat is on Top 11 % O_O).
P.S. So probably I have the equivalent of a RL "suburban" [high tech + "developed" + greenery] nerdy goth/emo/? people. It gives a weird twist of how the nation is.