It was narrated from Abu Hurairah that the Messenger of Allah (sal Allahu alaihi wa sallam) said: “The strong man is not the one who wrestles others; rather, the strong man is the one who controls himself at times of anger.” [The Book of Al-Birr: Sahih Muslim]
That is why we see that people with weak characters suppress their anger when dealing with their superiors but take it out on those weaker than them. A weak man will take his frustrations out on his family, a woman on her children, the rich on the poor. Giving free rein to one’s anger results only in crime against Allah’s creatures. It is natural to feel anger in certain situations but the successful person is he who is able to control the expression of his anger. Not all crimes in Islam are recognized as crimes in secular law, but what matters to a Muslim is how their action is viewed by Allah. Anger is justified when the crime is against Allah and his Messenger, but even then it is best handled with a cool mind.
Hazrat Ali (radi Allahu anhu) said: “A moment of patience in a moment of anger prevents a thousand moments of regret.”