I find this especially interesting, because although we don't think about it much that way, we grew up with someone who has a disability.

Our dad is pretty firm about not self-defining as disabled, but he is. He has always done poorly at standing. He can't really jump, or stand on one leg. In my memory, he has spent significant time on crutches.

But because it's a mostly-invisible disability, he manages to deflect all inquiries. Still, both of us know how to help a person larger than us out of a chair, and do it automatically. We evaluate walking surfaces at a subconscious level. Just a dozen little coping things that never really got explained, or talked about.