This piece in American Psychologist documents five weaknesses of the “hedonic treadmill” hypothesis:

individuals’ set points are not hedonically neutral. Second, people
have different set points, which are partly dependent on their
temperaments. Third, a single person may have multiple happiness set
points: Different components of well-being such as pleasant emotions,
emotions, and life satisfaction can move in different directions.
Fourth, and perhaps most important, well-being set points can change
under some conditions.  Finally, individuals differ in their adaptation
to events, with some individuals changing their set point and others
not changing in reaction to some external event.

The sad highlight for me:

of a number of recent reviews have concluded that individuals with
spinal cord injuries are less happy than are people in the general
population, with effect sizes in the moderate to large range (Dijkers,
1997, 2005; Hammell, 2004). However, the studies cited in these reviews
are often published in rehabilitation journals and are rarely cited in
psychological literature on adaptation.

Finally, Lucas (2005a)
used two large, nationally representative panel studies to examine
adaptation to the onset of disability. Participants in this study (who
were followed
for an average of seven years before and seven years
after onset) reported moderate to large drops in satisfaction and very
little evidence of adaptation over time. For instance,
individuals who were certified as being 100% disabled reported life
satisfaction scores that were 1.20 standard deviations lower than their
nondisabled baseline levels.
Thus, although people with paraplegia
and other individuals with disabilities usually are not subjectively
miserable, happiness levels do seem to be strongly affected by this
important life circumstance.

I’ve long been convinced that I would not adapt well to any grave misfortune.  Maybe I’m not as weird as I thought.