Anger is a positive emotion. It lets us know when something needs changing … fast! It releases energy to either run, stop and fight or pause to consider options.
The important thing is to release the anger appropriately and then let it go.
How do you release anger appropriately? One way is to exercise to blow off steam. Another is to confront a situation calmly and responsibly. Another way is to say I feel angry and need to regroup my thoughts, let you know how I feel about this, etc.
I believe in a 24 hour rule. Sometimes it takes time and perspective to calm down before confronting what angered you. Lingering anger, however, is toxic and ramps up stress.
Have you seen Melting Your Stress Within 30 Days? This is a good stress management tool.