Many people I meet judge the horse based on how the equine's behavior makes the person feel (safe, scared, confident, anxious, etc.) rather than having any acknowledgement or understanding of the animal's communication to learn how to decipher what the animal is experiencing in real-time and howthat will affect his future behaviors.
This leads to a lot of "he seemed fine" moments followed by excessive, dramatic, reactive, or even dangerous behaviors.
Illusions of the Safe Horse: Avoidant Horse Behavior