It's the slamming down on the ground that always gets me. It's kind of like being smashed in the small of your back with a 2 by 6. Or having someone run into you with an SUV at relatively low speed, over and over again. The truly annoying part, though, is that it doesn't hurt all that much AT THE TIME, which lets you do it repeatedly for hours. It hurts LATER. I'm beginning to consider sleeping downstairs on the couch, so I don't have to worry about whether I'll be able to make it down the stairs from my bedroom tomorrow morning.
Ow. Ow. Ow.
Oh - and that thing about pain being all in your mind? No. Not even close.