Anarchy* is neither theoretical nor Utopian.
It's a way to live among others without violating them. Probably the only way. It works in real life, every day, in the real world in which we live.
You already know this, I'm sure. If you don't know it yet, experience will drive the point home if thinking it through isn't enough for you.
*Or you can call it Voluntaryism. libertarianism, or abolitionism. Same deal.