In life, one will encounter many injustices. Here are some tips on handling them.
Start with asking yourself whether you are able to change the situation. Perhaps, getting angry about it repeatedly is a futile waste of time and energy that is better spent doing something more productive.
Some things are out of control, such as weather. Do not depend on those conditions to be met.
While you might not be able to control some circumstances, you are able to control your reaction to them. For example, in response to uncertain weather conditions on a day where an outdoor trip is planned, prepare for the inconvenient outcome by bringing jackets and umbrellas, or perhaps negotiate a different date.
Another example is that if the developers of a software refuse to implement your feature request, you could fork it and implement it yourself if you have sufficient programming skills, or you can find an alternative program whose developers might respect your feature request.
If people in your environment treat you poorly, leaving the environment might be easier than trying to repair it.
You might feel less angry about it after sleeping over it.
The brain uses the sleeping time to process information it received during the day. You might still be angry about it shortly after waking up, but when you go deeper into the next day, the anger of yesterday could be usurped by new information and tasks.
It is said that the brain tends to focus on negative things for the evolutionary reason that it increases the likelihood of survival.[1][2][3] Since we are no longer at an imminent risk of hostile attacks like in stone age, we have more space to focus on good things in life and create nice things, such as the device you are reading this on. Such devices were not available to people few decades ago.
Think of privileges you have that you might be taking for granted, such as being able to see, hear, and walk. Think of helpful tools that are available to you and you take for granted, but were not available few decades ago, such as computers, mobile phones, digital video cameras, modern car features, and the Internet as a searchable source of knowledge.
Perhaps, disasters will have positive side effects. This is known as the Nova effect.[4] For example, a data loss might have caused you to make more frequent backups that have later prevented a loss that would have been worse. If your partner cheated on you, it means it would have happened regardless at some point, so better sooner than later.
If it is an injustice that affects many people, establish contact to other people who are also affected by it. Knowing that one is not the only person to be affected by an injustice might alleviate the anger.