At the stable where I learned to ride and hunt, there was a huge bay stallion named Junior who was the meanest SOB ever born. All the students were taught to give Junior a wide berth; he'd even lean out of his stall to bite if you got close enough.
Only two people could ride him - the stable boss Dan, and a guy named Patrick.
One day, not long before I got there, Patrick was taking Junior around the ring, over some basic jumps. They approached the Wall, which was a bricky-looking jump about three feet high.
Junior decided at the last minute that he didn't want to clear the Wall, so he stopped short and let Patrick go over without him. After Patrick landed, then Junior decided to jump after all.
He landed on Patrick, and after that there was only one man who could ride him. Ugh.
That's terrible. There should have been no Jr. anymore.
Worst thing in the world is for people to keep (and God forbid breed) a horse or a dog or a cat with temperamental problems. I don't care how pretty it is, if it's mean, cut it -- if it's still mean, send it off to Alpo.