One reason I'm especially cautious about writing about my disability is what I call the "Touched by an Angel" syndrome -- where the subject becomes iconic of a "greater spiritual being", simply by virtue of their physical attributes -- akin to the romantic notions held by whites of the "Noble Savage" back in the 19th century.
As wonderful a songwriter as Si Kahn is, for example, the last verse of his song "It's not just what you're born with" makes me cringe just a little:
Between those who use their neighbors, and those who use a cane,
Those in constant power and those in constant pain,
Between those who run to evil and those who cannot run,
Tell me, which ones are the cripples,
And which ones touch the sun?
(let's face it: the lines can never be so clearly drawn)
I've even been told (with a straight face, no less) that I'd be a good medium, because disabled people have a purer spiritual essence.
I'm not afraid of sentiment, per se, but I recognize that the idea of physical disability carries with it multiple layers of cultural meaning, and if I want my own meaning to be clear, I have to be extra precise and careful with the words I choose.
And as for Joy, well, you just said my magic word! ;-) Extrapolating from my own personal experience, I came to the conclusion many years ago that all of life was created so that Joy could be experienced and shared. Period.
After all, I put up with all of the daily diffeculties and frustrations because, in the back of my mind, there is the hope that I might see the most beautiful sunset today, or taste an exquisite morsal, or feel laughter shake my frame. And if it's that way for me, who am I to say that it's not that way for oak trees and sperm whales, too?
I don't think there is a smidgen of "sentiment" in joy, frankly. It's much more powerful than that -- a deep taproot that connects us to life itself, joy reaches into darkness, and has something of a dark side itself... Dunno if that makes any sense, but there ya go... ;-)