Anger is often viewed as negative, but I’ve recently read a Japanese article in which anger is seen as the first feeling that will come out when you begin to accept your feelings.
They said that feelings are stuck up in order. From top to bottom: anger, sadness, joy, then fun.
So if you want to feel joy and have fun, you need to first accept your anger/let yourself express anger.
For people who have been repressing their feelings for long, or people who feel numb, the first feeling they experience is often anger or irritations when they begin to try to feel. That’s actually a good sign but they or people around them see it as negative so they repress it again, and go into a vicious circle. But if you see it as positive and let it out in an appropriate manner, you’ll then experience sadness, and eventually joy and fun.
I’m putting all this in a very simple words but I hope you’ll get the idea.