If I forgive my own child for misbehavior I am concerned that this is giving the wrong message. I might be creating a sense of entitlement for that child who now comes to expect forgiveness and so continues to misbehave.
As you forgive, be sure to included justice as well. Yes, forgive when you are feeling resentful, but then ask something of the child so that correction occurs. When you ask for fairness when you are less angry, then what you ask may be even more fair than if you ask when fuming with anger.