I have a bad habit of kneeling on the living room floor (carpet) in the evening, at the coffee table, futzing around on the iPad. For the last 5+ years, due to my damaged right knee, I'd then be unable to unbend my right leg for several minutes after I stood up.

Tonight I forgot not to kneel and ended up there for 20 mins or so — and managed to stand straight up and unbend my leg, then walk on it immediately without pain. Two weeks of physio, daily exercises. WHY didn't I get help sooner?