i remember when i was in college, there was a local Buddhist monastery that made the news. the buddhist monks spent 3 months working non-stop on a piece of art, made of tiny pieces of colored sand. all that hard effort paid off and out came a one of a kind, beautiful piece of art.
they took it to a river, and dumped the entire artwork in the water. why? because they wanted to practice their belief of "letting go".
you could hold onto that anger, let it build, or as some others have suggested, vent it in a safe way. Or, you could just let it go.