Some anger disappears when the unmet expectation underneath it finally gets named.

Much anger is an unmet expectation with the volume turned up. You wanted to be consulted, or thanked, or given more warning, and rather than surfacing as a plain want it surfaced as heat. Naming the expectation often deflates it entirely, either because you see it was unreasonable or because you realize you can simply ask for it next time.

When you are angry at someone, try finishing the sentence: I expected that you would. Say it plainly, first to yourself and then, if it matters, to them. The conversation that follows is usually shorter and far more useful than the argument you were about to have.