I train for a barn that is known for our slew of "problem horses" and almost 100% of the time, it's not the horse that's the problem
There have been MANY "trained" horses come to the farm, and I must admit their owners were very good trainers.
Very consistent too- one owner trained all of her horses perfectly how to rear when asked to load.
I now own one of above "trainer's" horses and am currently trying to break him of turning away from you and running off when he doesn't want to do something. It's very frustrating trying to fix things...and watching owners work with their horses reveals SO much. I can always tell when an owner was there over the weekend because some of my newly installed buttons always seem to be missing lol.