Hotels can exist on either side of the Haimish Line. You’ll find multiple generations at a Comfort Inn breakfast area, and people are likely to exchange pleasantries over the waffle machine. At a four-star hotel’s breakfast dining room, people are quietly answering e-mail on their phones.

Whole neighborhoods can exist on either side of the Haimish Line. Alan Ehrenhalt once wrote a great book called “The Lost City,” about the old densely packed Chicago neighborhoods where kids ran from home to home, where people hung out on their stoops. When the people in those neighborhoods made more money, they moved out to more thinly spaced suburbs with bigger homes where they were much less likely to know their neighbors.

In the 1990s, millions of Americans moved outward so they could have bigger houses and bigger lots, even if it meant long commutes. Research by Robert Frank of Cornell suggests this is usually a bad trade-off.

People are often bad at knowing how to spend their money — I’ve been at least as bad as everybody else in this regard. Lottery winners, for example, barely benefit from their new fortunes. When we get some extra income, we spend it on privacy, space and refinement. This has some obvious benefits: let’s not forget the nights at the Comfort Inn when we were trying to fall asleep while lacrosse teams partied in the hallways and the rooms next door. But suddenly we look around and we’re on the wrong side of the Haimish Line.

We also live in a highly individualistic culture. When we’re shopping for a vacation we’re primarily thinking about Where. The travel companies offer brochures showing private beaches and phenomenal sights. But when you come back from vacation, you primarily treasure the memories of Who — the people you met from faraway places, and the lives you came in contact with.

I can’t resist concluding this column with some kernels of consumption advice accumulated by the prominent scholars Elizabeth W. Dunn, Daniel T. Gilbert and Timothy D. Wilson. Surveying the vast literature of happiness research, they suggest: Buy experiences instead of things; buy many small pleasures instead of a few big ones; pay now for things you can look forward to and enjoy later.

To which I’d only add: Sometimes it's best to spend carefully so you can stay south of the Haimish Line.