There's a very interesting post on the blog of Berkeley Bionics, written by Gary Karp. It's almost an answer worth offering when wheelchair rider is approached by one of those people who say, more or less, I couldn't live like that ...
Karp writes, "What’s even more of a miracle is that we’re equally wired to accommodate being paralyzed if it does happen. Just as undeniably as we‘re wired to protect our lives by avoiding trauma, we are just as primally driven from the core of our souls to reach for life – even when we have become injured."
It's a thoughtful piece, but I would, from a perspective of 50-years of experience that a person does not so much "accommodate" (which implies an immediate comprehension) as "evolve" toward the existence on a different plane.
I do very much believe Karp's "souls reach for life" sentence is the soundest explanation, and reaching is an ongoing process, one that recognizes "life" is thoroughly subjective.
How a wheelchair rider perceives the world from a sitting position is almost entirely dependent on a person's ability comprehend the Great Is, the reality in which they live.
And in the most dispassionate of truths, reality contains all the joy necessary to be happy.