In Debt, the anthropologist David Graeber tells the story of Tei Reinga, a Maori...

In Debt, the anthropologist David Graeber tells the story of Tei Reinga, a Maori villager and "notorious glutton" who used to wander up and down the New Zealand coast, badgering the local fishermen by asking for the best portions of their catch. Since it's impolite in Maori culture {as in many cultures} to refuse a direct request for food, the fishermen would oblige-but with ever-increasing reluctance. And so as Reinga continued to ask for food, their resentment grew until "one day, people decided enough was enough and killed him."
This story is extreme, to say the least, but it illustrates how norm-following and norm-enforcement can be a very high-stakes game. Reinga flouted an important norm {against freeloading} and eventually paid dearly for it. But just as tellingly, the fishermen who put him to death felt so duty-bound by a different norm {the norm of food-sharing} that they followed it even to the point of building up murderous resentment. "Couldn't you just have said no to Reinga's requests?!" we want to shout at the villagers.