Sibling rivalry and jealousy often degenerates into violence. Boys and men are much more likely to carry a weapon than a female, but don't assume that only men act violently. Hostile, aggressive young people tend to come from broken, angry, violent homes. Anger is feeling mad in response to frustration or injury and expressing yourself in an impulsive manner without thought. You do not like the circumstances and usually you would like to get revenge.
Anger is a mixture of emotional, physiological, and cognitive elements.
It should be seen as distinct from the behavior it might provoke. In some instances, angry emotions are beneficial in that we take an appropriate and measured response to a real, not imagined threat. Anger can be caused by damaged pride, unrealized expectations, or repeated hostile fantasies. Anger can be used to justify oppressing others, to elevate our low self-worth, to hide other feelings, and to displace other emotions such as using aggression to hide fear. Beyond the cognitive and emotional state is actual aggression, or attacking someone or a group.