Explaining the incentive structure for participation in the bitcoin network is difficult. People's conceptions about internet services are trapped in a linear "producer-consumer" mental model. When there is no centralized entity producing the entire experience, their conceptual grasp weakens. The assembly line or energy transferrence of a watch mainspring across a gear train are easy to grasp, but what about when no component in the system gives a damn about the purpose of the other components?

The best that I have come up with when people ask me "how does bitcoin work?" is that it is like an ecosystem. Bees and wolves don't care that they are vital components of the food chakn; they are just following their base instincts. Similarly, miners, node runners, and users, by pursuing their own benefit (while constrained by the rules of system), and in doing so create a complex emergent machine.