Anger is for care.
Does it anger you when you see progress stopped?
When you see someone about to do something significant for others only to be stopped by a leader who says, "but before you do that, we need to set some rules."
That angers me. And it's not the leader interfering that angers me - it's the interference. And I anger because I care.
Anger is for showing care. It's for showing the world that what frustrates us – matters to us. It's for communicating to others, "hey, can this matter to you too?"
But, like foresight, anger stops becoming useful when it becomes excessive.
Care. But care just enough.