In and of itself, anger is not bad. It's one of the emotions we feel. It's normal. It's a signal that something is wrong. And, as we all know, it's what we do with the anger that either leads to insights and growth or to further problems.
As Sue Patton Thoele says in The Woman's Book of Spirit, "...examined anger is often an incredible teacher. Exploring our experience of anger non-judgmentally often helps us uncover valuable clues as to what we expect, what we want, what we fear, and where we feel especially vulnerable. Indeed, examined anger is a spiritual ally. Examined anger remains moist and movable, supple and malleable to our inquiring minds. From it, we can learn to stop accepting the unacceptable in terms of treatment directed toward us."
Yes, there's much to learn from our anger. Did we have expectations that went unmet? Is it about something we fear? Were our personal boundaries breached? Suppressing the anger doesn't make it go away. It only comes out sideways, or it lies in wait until something else happens—and then we blow sky-high, lashing out at others in inappropriate ways. Or we turn it inward, leading to depression.
Best we examine our anger when we feel it. Then we can learn from it. And then we have choices about what to do next—and those choices likely won't involve hurting others.