Cuz you're addicted to the sound of a shutter and that's a good thing for everyone. Your arm will get faster and feel better ... eventually.
Imagine the muscles you'll have acquired by then. You will need those arm muscles when you get a faster and still heavier lens.
I wouldn't try taking on Dinu in an arm wrestle because he must have arms of steel from toting all that monster glass around. Arms of steel, I say ... and eye's of a hawk ... and clever as a fox ... the mighty Photosaurus Rex! You notice, he doesn't complain about a sore arm, except perhaps when his wife makes him mow the lawn when he'd rather be birding.
