I have a friend that took a young horse pretty quickly through the levels because he just flat out didn’t pay attention to little fences. He went to his first Rolex (the Intermediate horse trials) when he was 6, he was 2nd at Rolex in the Advanced Horse Trials by less than a rail a few years later. He was a horse that needed at least a preliminary sized fence in front of him to pay attention. He was a cranky, grumpy, SOB that had no qualms about biting you if he thought he could get away with it–I refused to handle him without a stud chain because he was so strong minded.
I had another horse that I bought off the track that was a fruit loop in many ways. You could jump him over a single blue barrel but he would NEVER walk by one. He was always a freak about things on the ground. He had a 15 second window where you could catch ahold of him to get him into the start box in warm up. Sometimes he flat out wouldn’t go to warm up. He ran around the Rolex **** XC like a boss at 18 years old with his then owner. He would still spin and dump you on a hack.
Some horses are just goofy. If they’re talented you find someone to ride them that can bring out the latent talent and accept the goofy. Buck’s got to see the end of the rainbow with horses like this one because he’s got enough good horses to ride that he doesn’t need one that is difficult AND untalented.