Oh, I hear ya about that!!! Mr Gracie doesn't get it either. He has arthritis in his knee and eats vicodins like candy. Won't wear a knee brace, and just trudges along. But I know when it is really hurting him cuz he sits there and rubs and rubs and rubs it.
One day, when I asked him to open a jar for me (I have an electric opener now) he sighed, rolled his eyes and said "it isn't THAT bad, is it?" and I said "ok. It's my imagination. Meanwhile, go fix your own supper, but when you go to the kitchen, crawl on your bad knee. Oh, and when you want me to fetch somethng for you and I don't groan from the pain, YOU get it..on your fucking KNEE". I thought I saw a faint outline of a lightbulb go off over his head, too. Faintly. It didn't stay lit.
(gotta laugh at this shit. Or go crazy. Or off yerself. I choose to laugh at it for now).