Why should we care about petty corruption instead of grand corruption? It is precisely its pettiness that matters. In any social system, other forms of corruption involving large sums of money are unreachable for the majority. They are mere spectators and, eventually, angry victims of the collusion between bureaucrats, politicians, big firms, etcetera. But petty corruption has the potential to be popular, potentially available to everyone. Thus, when it is practiced by many, it spreads along the social system the belief that formal rules can be overlooked or bended; such that, people have...