A short clip came up on my social media feed recently which got me wondering: how do you decide that a horse is a lost cause training wise? What's the tipping point where you decide that the risks outweigh the benefits? The clip in question showed a horse rearing up so violently it flipped over onto it's rider. Now, say that hypothetically physical causes were ruled out and the problem was purely behavioural, say the horse had been poorly trained and it had this reaction any time somebody got on, would you decide that horse is too dangerous to continue training it? If so, why? If not, why? Also happy for people to share stories (good and bad) of horses with extreme behavioural issues.