It is a very bad habit to get anger over useless things. It often happens that a person gets angry and spoils their work and sometimes in annoyance he starts uttering the word of ingratitude and disbelief in Almighty Allah and destroys the wealth of his faith. That is why the Prophet ﷺ forbade his ummah to get angry.
Therefore, it is narrated in a Hadith that a man came to the Prophet ﷺ and said, “O Messenger of Allah ﷺ! Order me to do something but very little, He replied, ‘Do not be anger.’ He said, ‘Tell me something else.’ “Don’t be anger,” he asked several times, but each time the Prophet ﷺ said, “Don’t be anger.” This is a Hadeeth of Bukhari.صحیح البخاری، کتاب الادب ، باب الحذرمن الغضب،رقم ۶۱۱۶،ج۴،ص۱۳۱
It has been narrated in a Hadith that the Prophet ﷺ said that
A wrestler is not one who beats people, but a wrestler is one who controls himself in a state of anger.صحیح البخاری، کتاب الادب ، باب الحذرمن الغضب،رقم ۶۱۱۴،ج۴،ص۱۳۰
When is it bad, when is it good?
In fact, the goodness or evil of it are based on the occasion, if someone gets unreasonably angry and the effects are bad, then the it is bad and if someone gets angry due to some reason and the effects are good then the it is good.
For example, you get angry at the crying of a hungry, thirsty baby and you choke the baby because your anger, so this is completely inappropriate and bad, and if a robber is robbing you and because of anger you fired and killed the robber, then your anger is justified. So, it is good.
The anger which is condemned in the Hadith, is the same annoyance which is unreasonable and whose effects are evil. Obviously, in it, mercy and justice is replaced by cruelty, thanksgiving is replaced by ingratitude, faith is replaced by disbelief, so who can say that it is good? Of course, this is bad and it is a very bad habit. It is obligatory for every Muslim to avoid it.
Treatment of it (How to control anger in Islam)
When annoyance and rage overwhelm a man, the Prophet ﷺ said that
He should perform ablution immediately because the devil is the one who incites anger, and the devil is created from fire and the fire is extinguished by water, so ablution extinguishes the fire of anger.سنن ابی داود ، کتاب الادب ، باب مایقال عند الغضب ، رقم ۴۷۸۴، ج۴،ص۳۲۷
It has also been narrated in a Hadith that:
If a person gets angry while standing, he should sit down immediately, the anger will subside and if you don’t get angry even after sitting down, then lie down so that the anger disappears.المسند للامام احمد بن حنبل ، مسند ابی ذر ، رقم ۲۱۴۰۶،ج۸،ص۸۰
Every man and woman must protect themselves and their families from bad traits and habits. Adopt good habits and should adhere to it.