There is a spectrum of anger, the purpose of an emotion is not only to give you feedback and make you aware of certain things, but also modify your behaviour in order to deal with that situation in a better way.
Anger is supposed to alert you when there is the potential of failure and help you prevent it. Based on your performance in the world your emotions will change to make you react in an adequate way to the challenge, so this is why having a spectrum is important. Anger ranges from plain anger to frustration and finally to rage.
Every step on the spectrum will produce a different result in your behaviour, anger produces determination, frustration produces assertiveness and rage will make you react externally in a forceful way.
It is not always a guaranty that your anger is going to prevent loss, when anger fails to protect, you move from fight to flight in too sadness. As well as anger sadness goes on a spectrum that ranges from plain sadness, depression and finally anxiety.
Each step of the spectrum produces a different outcome in behaviour, as the general purpose of sadness is to bring clarity, depending on the level of sadness you experience your perception of the world will change.
At the level of sadness you are going to start to believe that something is wrong with the world around you, at the level of depression you start to realise that something is wrong with you, at the level of anxiety you barely understand anything you just know that it is going to happen again so you emotionally anticipate the pain.
At the middle of the spectrum is where self development happens. In order to experience frustration you have to fail at something over and over again, which gives you the power to assert yourself, if you have the knowledge to overcome the situation you are in assertivity will give you the energy behind the knowledge to apply yourself to the world.
There is a huge misconception to believe that assertivity is by any stretch of imagination a personality trait or something you get conditioned to have during your childhood, and if you don't develop it during your childhood you will never have it.
Assertivity is simply a self preservation instinct everybody posses one, you just require the self-discipline to cultivate it and maybe some knowledge.
However when there is a lack of understanding and knowledge assertivity will fail, which will make you withdraw into depression. This is a brilliant adaptation of your body to make you question yourself and examine your strengths and weaknesses as well as preserve energy and stop wasting it on ineffective strategies. There is a dark side to depression when you experience it frequent enough it will lead to low self esteem and more insecurity.
Rage is the last attempt to stay alive, this is where destroying other forms of life becomes essential if you are going to survive. Anger and frustration are not necessary win lose but rage definitely is.
This is what the story about the Hulk is all about, an anxious geeky scientist that becomes the victim of an accident that externalises his anger, as an uncontrollable destructive force that also gives him physical strength beyond his normal capacity.
At the level of rage there is very little understanding about the world other than the fact that you are in serious trouble and you need to protect yourself.
