Early this week, the mailbox fell over. It turns out that, underneath the fine 4x4 holding it up, there was a six-inch layer of soil that had once had wood in its ancestry. As far as I can tell, the only thing that's been holding the post up in recent months has been inertia, and a few toothpicks worth of surviving intact lumber.
In order to put a new mailbox right where the old one was (which really is the right location), I needed to excavate the remainder of the old post. Beneath the layer that had completely disintegrated, though, there was still a halfway decent spike of vaguely-square wood remaining, albeit a sort of rounded 2.5x2.5 by this point. This, sadly, meant that a simple post-hole digger didn't work: it couldn't close because of the remaining bit in the middle, so it couldn't get enough purchase to lift anything out.
So this afternoon's recreation was a couple of hours on my knees, using a trowel to loosen the dirt (and rocks -- well, actually mostly rocks with dirt acting as mortar) around the post, and digging it out with my fingers, feeling like nothing quite so much as a collie trying to retrieve a mastodon's femur that he's accidentally buried too deep. (Or, really, an archaeologist from 2001, watching the monolith emerging as I cleared the soil around it.) Fortunately, I managed to get the stump loose while I was still only 3/4 of the way down to my shoulder in the ground: if the bottom had actually proved out of reach, I would have gotten rather cranky.
Anyway, the mailbox is now sitting placidly on a new post, pretty much right where it's always been. And I have that combination of satisfaction and odd cramped muscles that comes with unusual manual labor...