At the barn I just moved from, I have spent the last seven or eight months watching the unfolding drama of a family who had bought their first pony for their son. Unfortunately, the pony is three years old, greenbroke and sparky, and they're clueless. It was quite sad, as they are a sweet family, but in over their heads with a pushy three year old who needs experienced handling. Among other things, the mare got into the regular habit of bucking the kid off in the canter and he had become nervous about riding and being around her. I lunged him on my trained-to-the-nines schoolmaster to try to get his confidence back, which sort of worked, but while he was handling my horse, grooming and tacking her up, you could see in his whole body language and the way he was around horses where all the problems with the youngster came from. Anyway, after his ride on my mare, he decided he liked horses again and started taking more lessons from the barn owner on his pony, who dutifully stuck with her habit of bucking him off at the canter.
I'm not "the trainer," or "a trainer," although I have trained horses and riders, but in this instance I was just another lowly livery who could only stand back, watching the trainwreck and offering the odd (and usually ignored) suggestions. After much consideration, I decided not to step in more than that, as the owner of the stable had become their trainer and it's her stable. In any case, they weren't making much progress in improving their relations with the mare and the son completely lost interest and didn't want anything to do with horses. So the wee mare is up for sale.
It's sad and frustrating to watch these things. They were so enthusiastic about horses and had bought the young mare on the grounds that horse and kid could "grow up together." Then found out the hard way that this doesn't really work.