Do you know what happens when a volcano erupts? It throws hot lava everywhere and burns everything nearby. Anger, when we let it take over, is like that: we yell, we say ugly things, and we end up hurting the very people we love most, even without meaning to.
Feeling angry isn't wrong, everybody feels it, even grown-ups. The secret is what we do with it. You can notice the volcano starting to bubble inside and let the pressure out slowly: taking a deep breath, drinking some water, counting to ten before speaking.
Truly strong people aren't the ones who shout the loudest, they're the ones who can hold back their own volcano. And the best help for that is Jesus: when we ask Him, He makes our heart calmer and more patient, a little more each day.
You feel the anger; what you do with it, you choose.