I believe I have figured out why I kept postponing the casting on of the second sock. Somehow, I had built up in my mind that it was going to be a fiddly knit. Which it isn't. Which I would have known if I had just cast on the second sock right after I finished the first one. But no, I kept putting it off, and the bogeyman kept getting bigger. Until today. I was just sailing along. which is why I didn't realize how long I had been knitting until my back started to complain.