This question generally presupposes a misunderstanding of the physiological purpose and phenomenological experience of happiness. Happiness by its nature is not sustainable. Contentment and well being with a high happiness surface area and a low suffering surface area is sustainable. This does not look very dramatic from the outside, and is poorly captured by many metrics. Neuroticism might be one of the best psychometrics, with most people experiencing only a small decrease over a life time, with some experiencing a very large one.
>Neuroticism might be one of the best psychometrics, with most people experiencing only a small decrease over a life time, with some experiencing a very large one.
Would you say this is more of a nature or nurture effect? I.e. some people naturally decrease in their neuroticism levels as they mature and most people don't, OR a small percentage of people stabilize their lives and statuses in their respective societies, which presumably leads to a decrease in their neuroticism levels.
