Entitled: "La Col癡re (Wrath) caricature of facial expression; three men in aggressive postures. Color lithograph by Louis-L矇opold Boilly, 1824. Anger is an emotional response related to one's psychological interpretation of having been threatened. Often it indicates when one's basic boundaries are violated. Some have a learned tendency to react to anger through retaliation. The external expression of anger can be found in facial expressions, body language, physiological responses, and at times in public acts of aggression. Humans and animals, for example, make loud sounds, attempt to look physically larger, bare their teeth, and stare.