Horses are always watching and judging you, which means they truly are nags.
According to a recent study, horses are constantly studying your expressions, and will remember and judge you if you make an angry face around them. Scientists knew that horses could recognize facial expressions, but the fact that they can remember these expressions and base their future reactions to the makers of those expressions is new.
If you’ve ever wondered what a horse is thinking, now we know it’s, “You should smile more.”