Heh, weird. I had the same experience with the hands again today, down to making the same mistake--I was sure I had my fingers interlaced this time, but still didn't. If I remember, I might try sitting down to meditate some time with my fingers deliberately intertwined, to see if I get the same effect.

I've also been demonstrating to myself that trying to meditate when I'm very tired is almost useless. After the last session I wrote about, I did another one at the end of the night right before I went to bed, and I went long periods not even remembering I was supposed to be focusing, never mind actually focusing. But of course this afternoon, well-rested and just out of a shower, I did fine. That sitting was also a bit shorter than what I've tried before--back to 25 minutes instead of 35. I'm still tweaking that.