They are in debt out the nose.   Everybody is.  And that is dangerous.   In a healthy economy, somebody might take out say a million dollar loan, and build a factory that creates say two million in wealth, so the debt is sustainable.   However, today, most debt is leveraged into things like housing bubbles, stock bubbles, and other things that aid consumption, but don't PRODUCE any real new wealth.   

Our society is going to learn the hard way, that extra low interest rates, don't "stimulate" the economy, and DO create bubbles.    A lot of people want low interest rates, but in truth we should want high interest rates, so capital can be allocated by the market, and not by the central bank printing up money.   Central bank imposed low interest rates do not help the real people who produce real wealth, it destroys them.