(I've been doing a lot of personal research over the past 2 weeks on the subject of anger. Here is a summery of some of the things I have found. Perhaps they may be of interest to someone.) 

____________________________________________________________ 

Anger  noun

1. a strong emotion; a feeling that is oriented toward some real or perceived grievance 

2. the state of being angry 

3. belligerence aroused by a real or perceived wrong or threat (personified as one of the deadly sins)

____________________________________________________________

Causes

Most commonly, 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 his anger in an intentional, personal, and controllable aspect of another person's behavior. This explanation is however based on the intuitions of the angry person who experiences a loss in self-monitoring capacity and objective observability as a result of their angry emotion.

According to Britannica Encyclopedia, an internal infection can also cause pain that in turn can activate anger.

Key Points

- Being angry or frustrated is just like being under the influence of a drug. It prevents you from rationalizing and thinking logically.

- Anger is caused by a combination of an irrational perception of reality and a low frustration point.

Internal Sources of Anger

Our internal sources of anger come from our irrational perceptions of reality. Psychologists have identified four types of thinking that contribute to anger.

1. Emotional reasoning. People who reason emotionally misinterpret normal events and things that other people say as being directly threatening to their needs and goals. People who use emotional reasoning tend to become irritated at something innocent that other people tell them because they perceive it as an attack on themselves. Emotional reasoning can lead to dysfunctional anger in the long run.

2. Low frustration tolerance. All of us at some point have experienced a time where our tolerance for frustration was low. Often stress-related anxiety lowers our tolerance for frustration and we begin to perceive normal things as threats to our well-being or threats to our ego.

3. Unreasonable expectations. When people make demands, they see things as how they should be and not as they really are. This lowers their frustration tolerance because people who have unreasonable expectations expect others to act a certain way, or for uncontrollable events to behave in a predictable manner. When these things do not go their way, then anger, frustration, and eventually depression set in.

4. ‘People-rating’ is an anger-causing type of thinking where the person applies a derogatory label on someone else. By rating someone as a “*****” or a “bastard,” it dehumanizes them and makes it easier for them to become angry at the person.

Using anger to control

One aspect of anger is that it can be an effective method of control; that is control over situations and control over people.  It can overpower the opposition, and it can create timidity and even fear on the part of other people so that they dare not cross or disagree with the angry one.  But this kind of behavior can be harmful, and even devastating to relationships.  It also brings about an unhealthy situation in which other employees, friends, or family members get together to plan how to circumvent the problems created by the angry one, which means that he or she is detrimentally excluded from councils which clearly are of the utmost importance.

In many cases, it is wise to consider the person more than the issue.  One may win an argument, but the other individual may be hurt and alienated.  People frequently get so involved with the subject at hand that this is a fact that escapes them.  Children complain about an angry parent, and, in later years when they look back, they hardly remember the issues, but they do remember the anger.

It is tragic when a person is afflicted with what is called ‘floating hostility’.  This is hostility that is just below the surface and which frequently erupts.  It can spew out on a family member or a fellow worker, or on the people one comes in contact with every day: the waiter, the gas station attendant, or the salesperson.  The angry one justifies his or her anger by the event, "He deserved it; look what he did."… ignoring the fact that it causes hurt feelings.  The angry one either does not realize it or does not care.

At various times, as there are cyclical swings in the field of psychiatry, people are encouraged to express their anger, to "let their feelings out."  A common phrase is: "My emotions should be validated."  Clearly, if one's feelings are bottled up and the person does not have reasonable freedom to express them, the situation should be addressed, and many a person has been helped by therapy in this regard. 

But we have also seen situations in which the "Express-your-anger" concept has been overdone, and has been taken as a license to "let fly", to the detriment or loss of relationships.  This questionable method is frequently used to control other people, perhaps unconsciously.

Can a person modify one's excessive anger and floating hostility to benefit relationships?  It depends on how much he or she values the relationships.  But, even more, it depends on the ability to identify the problem and the willingness to change.  People have such a capacity for self-anesthesia that they often are not aware of some of the things they are doing in life.  Individuals with floating hostility continually justify it by citing the situations that confront them, rather than realizing it is their attitude that brings them trouble.

Centuries ago Aristotle said it best, "Anyone can become angry - that is easy.  But to be angry at the right person, to the right degree, at the right time, for the right purpose, and in the right way - that is not easy."

Some people justify their actions with the classic inevitability theory: "My father was angry.  I was born angry.  I am angry.  I will continue to be angry."  However, with the identification of the problem and the desire, behavior can be modified.  After all, there are people who formerly got angry very easily, and who do not any more!  And there are those who dropped other unfortunate characteristics which their parents had, such as overweight, excessive drinking, and unfaithfulness and which they at one time thought were dictated by birth.  Despite what some people think, such personal traits are not irrevocably inherited.

__________________________________________________________

Robots require only a source of energy and a series of commands to function. They're purely logical. So…why are people so much more complicated?

The answer can be summed up in one word:

“Pride."

some say that getting angry is like eating poison then waiting for the other person to die

This needs to stay in the forums, like the rest of your personal research!