Sometimes when I'm asked "How are you?" I want to answer "How much time do you have?"
But I don't. Usually...
Anyway, on to the flavors of "can't"...
There's "forever can't." You can't fly. You can't outrun a cheetah. You can't outswim a dolphin. And your answer is... who cares? I can do stuff they can't. It all works out in the end.
There's "temporary can't." I took an anime-voiceover class this weekend. Absolutely loved it. Was sometimes quite bad at it. Was sometimes good at it. It's something that I can't do well...now. Yet, if that's what I choose. But I learned a lot. Oh, what I learned. I was the worst person in the room and benefitted thereby. "Temporary can't" can be encouraging. Can be empowering. Can even be fun.
There's "suddenly can't." Every living creature gets to experience that; always, more than they'd like to. We MSers, we get precisely our allotted share of these "can'ts," but they come to us at a vastly accelerated rate. It's no more or less welcome, but we don't get the balm of age, time, or anything else, really (given that we're living a life with poor insulation) that eases those "can't's" entry into our lives. I just got two whoppers last weekend; I can't take organ jobs any more, I can't drive my stick-shift truck any more. The way I've been "walking" (some authors have described walking as a "controlled fall" and I'm way too close to that point), I'm concerned that simply walking is going to become a "suddenly can't," and precisely when I least expect--or need--it to happen. Although, with my perspective on MS, it's going to happen at a moment, and in a way, that is darkly and twistedly funny, the sort of joke that's always described as "you just can't write things like this."
"Suddenly can't" is a gift. But you don't know it yet. Alas, you can't (forgive the choice of words) recognize the gift that it's going to bring you, before that gift arrives. But it nonetheless heralds a gift; a perfect gift, which the universe will inevitably place right into your hands, at just the perfect time--at the moment that you're ready to receive it.
Everything horrible that has happened in my life, everything that I regarded as "nothing worse than this has ever, or could ever, happen to me," that left me wracked for months or sometimes even for years, has caused something absolutely wonderful to happen. And that wonderful thing would not, could not have happened, but for the horror that enabled it to come to pass.
God works in a mysterious way. And usually one which, in the fullness of time, will make you laugh.