I finally figured out why.
At, oh, about 1 AM I was awake yet again, staring at the ceiling and wondering why. And then I realized something.
The (&$#@! downstairs neighbors were still playing their ^(&$^@# music too loud. I could hear it, and that was what was waking me up. Ah-ha!
(They've recently taken to playing music in their bedroom. Mine is directly above it, and the sound comes up through my floor very nicely, thank you.)
Unable to get back to sleep, I went downstairs and asked them to turn it off. They say "oh, okay." (No appologizing for waking me up at 1 in the bloody morning, but whatever.)
It all seems fine until I settle in to go back to sleep. And then slowly I start becoming aware of a rhythmic pounding... Oh. They didn't turn it off, they just turned it down. Look, fuckhead, what part of OFF didn't you understand!?! What part of "pissed-off upstairs neighbor knocking on your door at 1 AM" wasn't clear??
So now I'm out in the living room, hoping that maybe out here, I can get some sleep. Of course, it just so happens that they decided to finally do something about the wet laundry that has been sitting on top of the drier for at least four days (that I can account for.) It seems only in character that they decide to do this in the middle of the night.
I want my house. I want my house so that next time the neighbors underneath me make noise in the middle of the night I can fumigate their little asses and kill them and no one is going to send me to jail over it. Grr!!