Saying the unsayable in race relations.
When we wrote about the fact that the Japanese didn't loot each other after the recent tsunami, one reader chalked it up to class. This person pointed out that the major difference between Japan, with no looting, and New Orleans, where looting was rampant, was that New Orleans has an extremely generous welfare system which leads people to believe that they're entitled to whatever they can grab.
We argued that race might have something to do with it. For thousands of years, Japanese had to get along well because any village that didn't cooperate would starve when the rice crop failed. This went on so long that anyone who wouldn't cooperate was bred out of the gene pool.