A simple model of lifetime happiness

From Jeff:

Suppose that what makes a person happy is when their fortunes exceed expectations by a discrete amount (and that falling short of expectations is what makes you unhappy.)  Then simply because of convergence of expectations:

1. People will have few really happy phases in their lives.
2. Indeed even if you lived forever you would have only finitely many spells of happiness.
3. Most of the happy moments will come when you are young.
4. Happiness will be short-lived.
5. The biggest cross-sectional variance in happiness will be among the young.
6. When expectations adjust to the rate at which your fortunes improve, chasing further happiness requires improving your fortunes at an accelerating rate.
7. If life expectancy is increasing and we simply extrapolate expectations into later stages of life we are likely to be increasingly depressed when we are old.
8. There could easily be an inverse relationship between intelligence and happiness.