It seems like Americans use credit cards for everything. It’’s a lot easier to spend money that you don’’t see, isn’’t it Many Americans spend money that isn’’t even there — and get deeper and deeper in debt. Why do so many people spend more than they have "Buy now, pay later" has become an American way of life. Recently, American households spent nearly 11 billion dollars more than they earned, creating negative saving rate. There are two ideas — one, living within your means, and the idea that living on debt is a great equalizer (平衡装置). They both have validity because it is important that someone live within their means over their lifetime. When people are young and they are earning money but they have very little savings, they almost have to borrow in order to own a house or own a car. But as they grow older, they should develop the habit of saving, so that by the time they reach the end of their earning life, they have savings to live on in retirement, and live within their means. "Buy now, pay later" is worked very well for us in the 90’’s, but one suspects it won’’t work forever. The only think that concerns me is that Americans are so contented, so optimistic, so unconcerned about any bumps in the road that many American households, not all of them, but many American households are very heavily extended in personal credit. A lot of credit card debt; people are paying very high prices for houses and borrowing heavily against those prices; and if we do run into a bump in the road, a recession, there are going to be a lot of households, not all of them, but many households that’’ll be severely squeezed. That means we’’re more vulnerable to serious financial distress than Japan is. Japan has been in financial distress for ten years, but one reason it’’s been able to weather that is that the households had been very conservative, had a lot of savings, were very liquid, and were able to weather difficult times. And many American households would now be less able to do that because they are to heavily in debt. 50. What’’s the chief concern of the author