As a person who has ridden horses I would say horses that don't poop. After that, horses that don't throw you randomly, need constant vet checkups, make tons of

As a person who has ridden horses I would say horses that don't poop. After that, horses that don't throw you randomly, need constant vet checkups, make tons of dust, smell funny, or bite. Far in the distant horizon of the problems with horses is speed.