We have newish people at my barn who got a new yearling last September. Super cute, super well bred QH filly. Very sociable, very friendly, and (the major issue), very smart. The people who have her haven’t had horses since they were teens (30+ years ago) and went with the Clinton Anderson methods . Going so far as to have a ‘certified’ CA trainer out for an entire day of training. As many times as he hit this poor filly, I was so upset I had to leave (and I wasn’t even in the arena with them).
I have watched this poor filly go from friendly and sociable to not wanting a thing to do with people. She was a pretty nice mover, and now is so choppy because she’s waiting to get jerked on to go the other direction. It really is very sad. And now they just bought another yearling. Sigh.
That being said, when I got in to horses 30 years ago, my gelding had some super duper spoiled rotten issues. I had Parelli’s 7 games book and took a few of those exercises which really did help quite a bit. I think that was before the whole NH just blew up in to what it is today.
Also took that same gelding to a CA-based groundwork clinic. Had I known better and had more confidence, I would have just left. It was just dumb. I felt it was more about making the horse guess what I wanted than just asking them (which I finally did when the instructor moved on). He was so mad about that clinic that he ran me over the next day, and he’d never done that. I couldn’t even blame him. One of those lessons learned the hard way.