The external expression of anger can be found in facial expressions, body language, physiological responses, and at times public acts of aggression. Animals, for example, make loud sounds, attempt to look physically larger, bare their teeth, and stare. The behaviors associated with anger are designed to warn aggressors to stop their threatening behavior. Rarely does a physical altercation occur without the prior expression of anger by at least one of the participants. While most of those who experience anger explain its arousal as a result of "what has happened to them," psychologists point out that an angry person can very well be mistaken because anger causes a loss in self-monitoring capacity and objective observability.
Modern psychologists view anger as a primary, natural, and mature emotion experienced by virtually all humans at times, and as something that has functional value for survival. Anger is seen as a supportive mechanism to show a person that something is wrong and requires changing. Anger can mobilize psychological resources for corrective action. Uncontrolled anger can, however, negatively affect personal or social well-being and impact negatively on those around them. It is equally challenging to be around an angry person and the impact can also cause psychological/emotional trauma if not dealt with. While many philosophers and writers have warned against the spontaneous and uncontrolled fits of anger, there has been disagreement over the intrinsic value of anger. The issue of dealing with anger has been written about since the times of the earliest philosophers, but modern psychologists, in contrast to earlier writers, have also pointed out the possible harmful effects of suppressing anger. Displays of anger can be used as a manipulation strategy for social influence.