Horse wanted to run through his trot every time we faced the barn, and wanted to slow down to a crawl every time we faced away from it. I kept forgetting about this, and so every time I gave him the usual squeeze into a trot he'd leap out if we were facing the barn, or I'd have to give him extra leg if we were facing away from it. So the transitions going up were either super fast, leading him to run through the trot, or super slow and clonky.
At every corner, he start either taking me RIGHT into the rail or cutting the corner...so then I had to start guessing which one it was going to be. Trainer was encouraging me to stay a mental step ahead, but it seems like if I guessed "scrape the rail" it would turn out that he'd planned to cut the corner (and vice versa). So I spent the lesson either making these big wide swoopy turns or really short harsh ones - and then the length of the arena was getting spent correcting whatever I'd screwed up in the turn...just in time for another turn.
And with all of this, my hands were noisy and I kept forgetting to keep my heels down. And I kept losing my balance (see sharp turns and lots of corrections, above).
Usually I have a lot of patience with myself on this stuff, but today I want to pull my hair out. The only silver lining is that I almost always picked up the correct diagonal, and that I was managing to stay on it (or switch to it) while all this other stuff was going on. So: Diagonals Going Well. Pity about the reining...