“Horses are a lot like people,” says renowned horseman Mark Rashid. “When there are gaps in understanding, confusion, and thus frustration, worry, and even anger are sure to follow.” Horses often grow up with these “gaps” in their training and education. When this happens, it can be difficult for the horse to be a willing partner to a human, and he may need to be “restarted”—that is, given a second chance to...