structural:summarization
Causes

Some animals 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. Displays of anger can be used as a manipulation strategy for social influence.

People feel really angry when they sense that they or someone they care about has been offended, when they are certain about the nature and cause of the angering event, when they are convinced someone else is responsible, and when they feel they can still influence the situation or cope with it. For instance, if a person's car is damaged, they will feel angry if someone else did it (e.g. another driver rear-ended it), but will feel sadness instead if it was caused by situational forces (e.g. a hailstorm) or guilt and shame if they were personally responsible (e.g. they crashed into a wall out of momentary carelessness). Psychotherapist Michael C. Graham defines anger in terms of our expectations and assumptions about the world. Graham states anger almost always results when we are caught up "... expecting the world to be different than it is".

Usually, those who experience anger explain its arousal as a result of "what has happened to them" and in most cases the described provocations occur immediately before the anger experience. Such explanations confirm the illusion that anger has a discrete external cause. The angry person usually finds the cause of their anger in an intentional, personal, and controllable aspect of another person's behavior. This explanation is based on the intuitions of the angry person who experiences a loss in self-monitoring capacity and objective observability as a result of their emotion. Anger can be of multicausal origin, some of which may be remote events, but people rarely find more than one cause for their anger. According to Novaco, "Anger experiences are embedded or nested within an environmental-temporal context. Disturbances that may not have involved anger at the outset leave residues that are not readily recognized but that operate as a lingering backdrop for focal provocations (of anger)." According to Encyclopædia Britannica, an internal infection can cause pain which in turn can activate anger. According to cognitive consistency theory, anger is caused by an inconsistency between a desired, or expected, situation and the actually perceived situation, and triggers responses, such as aggressive behavior, with the expected consequence of reducing the inconsistency. Sleep deprivation also seems to be a cause of anger.