In "No Country for Old Men" there exists a significant connection to today's society. The connection is the breakdown of morals and how this manifests itself in increased drug use, murder, greed, and distrust of others. The novel by Cormac McCarthy, as well as the movie based on the book (by Joel and Ethan Coen) shows quite dramatically how moral deterioration hardens people. I agree with the above post that the characters are indeed tempting fate. They do this because of their lust for money. Therefore, in their lust and greed they do not seriously consider the results of their illegal and dangerous actions.
Among thieves, criminals, and other nefarious folk, there is a law of injustice - a way of doing things within the paradigm they are living in. It is, in a sense, a set of rules to be played by, even as they perform illegal acts. Therefore, in the book and the film, Anton Chigurh plays by his own weird set of rules and inflicts punishment on those who do not play by his rules.