A good school is a relative concept, and the better schools are located in more expensive neighborhoods. But when everyone bids more for a house in a better school district, they succeed only in bidding up the prices of those houses. As before, 50 percent of all children will attend schools in the bottom half of the school quality distribution. As in the familiar stadium metaphor, all stand, hoping to get a better view, only to discover that no one sees better than if all had remained seated.

In short both the things we feel we need and the things available for us to buy depend largely—beyond some point, almost entirely—on the things that others choose to buy.

One reason that might motivate a worker to accept a riskier job at higher pay, for example, would be that doing so would enable him to bid more effectively for a house in a better school district. But if other workers did likewise, none would achieve the goal they were striving for.

Many social critics wag their fingers at what they perceive to be frivolous luxury spending. But that misses the point that consumption norms are local. It's not just the rich who spend more when they get more money. Everyone else does, too. The mansions of the rich may seem over the top to people in the middle, but the same could be said of middle-class houses as seen by most of the planet's seven billion people.

The fact that many private expenditures are mutually offsetting actually happens to constitute a remarkably good bit of fiscal news. Mutually offsetting spending patterns are wasteful in the same way that military arms races are. In such situations, if each party spends less, nothing is sacrificed, yet resources are freed up that can be put to much better uses.

When the economic pie grows larger, it's always possible for everyone to have a larger slice than before. So it's really in all of our interest to make the economic pie larger by eliminating waste whenever and wherever possible.

If the search is for examples that contradict the predictions of standard economic models, a good rule of thumb is to start in France.