Continuing to fail to correct the obvious

Today I had a great lesson with John, but a couple more slices of humble pie. First, I forgot about riding a bendy line from center to center, and couldn't tell why sometimes I got it right, and why sometimes we were a half stride off. Then, I kept forgetting to look at the next fence around a roll back corner, even though by the time I forgot it the 10th time or so I wanted to kick myself for overshooting and having to scramble to fix it. Third, I couldn't remember to half halt around the corners, while maintaining impulsion (key to this problem? I have been using my legs last instead of first in the half halt, so I lose impulsion when I half halt), so that we came into the fences nice and round. And fourth, Charlie has hoodwinked me in the half halts. He has cleverly been tucking his head, so I feel him go lighter in my hand, but I don't feel the "poof" in his back. This is because he isn't really half halting (see above). These were all perfectly timed for what looked like it would be hard on the novice courses, and I'd way rather know what my mistakes are, but I would like, every once in a while, to not look like a solid D student. I was telling myself, "C'mon Martha, pull it together" but as soon as I focus on one thing, another one drops off my radar and when I focus back on the dropped one, I drop a new thing.