Many people, when first approaching a horse, are fearful. They see a wild-looking animal twice their size and get intimidated. That is the opposite of how you want to feel when approaching horses. Horses are prey animals, they will always be more scared of us than we are of them.

Them being prey animals also means that they can sense fear. This is useful for horses in the wild when living in herds. If they sense fear from a horse in their herd, it is likely a predator or threat is nearby. This allows them to send each other emotional signals that they need to relocate in silence.

Furthermore, this sense is not limited to only horses. Horses can sense fear in any animal, especially humans. So, horses are not thinking of intimidating humans or hurting them, they just react to their surroundings. If a human is scared when approaching a horse, the horse will also get scared. Then everyone is scared and it is not a good time!