Imagine you traveled back in time and met Bob the Caveman. And imagine you tried to tell him about cars. "They're made out of metal...umm, it's like rock but harder, and they are empty inside, and they have wheels...these are like feet, and they go really fast and they are powered by fire. They can cover a day's walk in the time it takes to eat a meal." Bob might find this a bit far out, but it's within the realm of possibility.
Now, imagine you tried to tell him that people drive them around according to very strict rules, and though there are millions, going very fast, they rarely hit each other. Everyone follows little bits of paint on the ground -- that you have to look for to notice -- and obeys colored lights. Now Bob would laugh. How could so many people be so organised, with very little enforcement, just some signs, lights, and paint!? How can they, when two lanes merge, weave cars together one by one -- acting in unison with total strangers? How can they take turns at a stop sign, and let pedestrians walk in front of them? How does anyone ever manage to change lanes in heavy traffic? The amount of consent created over driving, is far more amazing than the cars themselves.