Where is My Brain?

As impossible as it seems to be, I seem to have made yet another mistake in the armhole decreases for my Shapely Tank. I was so fixated, I'm guessing, last night on not making the same mistake that I made a new one. So now I will spend my night ripping back to where I ripped back to last night. Or maybe I'll work on something else for a while since Shapely and I seem to be having communication issues. I think part of the problem is that the shaping is so simple I don't give it much attention and do other things while I'm knitting like watch tv and read blogs. What I should be doing is watching my knitting and counting stitches to make sure I'm not screwing up.