The two main lessons, as I read this paper, are a) pain is less bad when the sufferer can see the endpoint, and b) pain is less bad when the sufferer feels in control to some measure.
The concluding discussion of "happiness economics" is on the mark:
…my personal reflections are only in partial agreement with the literature on well being (see also Levav 2002). In terms of agreement with adaptation, I find myself to be relatively happy in day-to-day life – beyond the level predicted (by others as well as by myself) for someone with this type of injury. Mostly, this relative happiness can be attributed to the human flexibility of finding activities and outlets that can be experienced and finding in these, fulfillment, interest, and satisfaction. For example, I found a profession that provides me with a wide-ranging flexibility in my daily life, reducing the adverse effects of my limitations on my ability. Being able to find happiness in new ways and to adjust one’s dreams and aspirations to a new direction is clearly an important human ability that muffles the hardship of wrong turns in life circumstances. It is possible that individuals who are injured at later stages of their lives, when they are more set in terms of their goals, have a more difficult time adjusting to such life-changing events.
However, these reflections also point to substantial disagreements with the current literature on well-being. For example, there is no way that I can convince myself that I am as happy as I would have been without the injury. There is not a day in which I do not feel pain, or realize the disadvantages in my situation. Despite this daily awareness, if I had participated in a study on well-being and had been asked to rate my daily happiness on a scale from 0 (not at all happy) to 100 (extremely happy), I would have probably provided a high number, probably as high as I would have given if I had not had this injury. Yet, such high ratings of daily happiness would have been high only relative to the top of my privately defined scale, which has been adjusted downward to accommodate the new circumstances and possibilities (Grice 1975). Thus, while it is possible to show that ratings of happiness are not influenced much based on large life events, it is not clear that this measure reflects similar affective states.
As a mental experiment, imagine yourself in the following situation. How you would rate your overall life satisfaction a few years after you had sustained a serious injury. How would your ratings reflect the impact of these new circumstances? Now imagine that you had a choice to make whether you would want this injury. Imagine further that you were asked how much you would have paid not to have this injury. I propose that in such cases, the ratings of overall satisfaction would not be substantially influenced by the injury, while the choice and willingness to pay would be – and to a very large degree. Thus, while I believe that there is some adaptation and adjustment to new life circumstances, I also believe that the extent to which such adjustments can be seen as reflecting true adaptation (such as in the physiological sense of adaptation to light for example) is overstated. Happiness can be found in many places, and individuals cannot always predict their ability to do so. Yet, this should not undermine our understanding of horrific life events, or reduce our effort to eliminate them.