So, the short answer to my question is force. I don't think a lot of people really think about this, because they don't really think about taxes. They just sort of unquestionably go along with it. Maybe because they have always been told "there are two things sure in life: death and taxes". If you can manage to convince people that government is force very few are then willing to question is government having a monopoly on force a good thing. But, should you even bother?
I think there is a better approach. If you do get some one to the point where they say "Ok, yea government is force. So what?" Ask them, "why do we need force to deliver the mail?". I think that one question sums up how ridiculous it is that the government is involved in mail delivery. Do we need force to build the roads? I know force can be used to build things, like the pyramids in Egypt, but do we need to do that in a supposed civilized society. Now I know there are some things that people will say do need the backing of force, like removing a murder from the streets. Everyone will come up there own idea of where the line needs to be drawn, but I think as long as we are getting people to question why is government doing this the line is moving in the right direction.
Some anarchists want to argue about who is living a more principled anarchist life style. They are great arguments to have about theory, but I live in the real world. As long a government is getting smaller and my freedom is increasing I am happy. Unfortunately it seems like that is rarely ever the case.