I guess it depends what the anger stems from. In some situations it is good, as it gets us out of a bad situation.
In others it is just damaging to ourselves and others.
I was hurt by someone, a long distance relationship, so we never met.
I started off by "God, right now I hate him, but I know you don't want me to, can you help?"
I prayed that (or similar things) over and over and over ....
Eventually, the feeling of hate subsided.
So I started praying "Lord, I know you want me to forgive him, but I can't yet, can you help me?"
and I prayed that over and over and over
until I was able to say "Ok God, I am still angry, and I will probably rant about it again, but I think I forgive him,
do help me if I forget that I did so I can do it gain

)