In the financial advisory business, I was one of the biggest opponents against then Fed Chairman Greenspan's decision to bring down interest rates so low after the tech-bubble burst. By decreasing interest rates to a 46-low, Greenspan, I believed, was setting the stage for massive amounts of borrowing by consumers.

And that's what consumers did. They took advantage of decreased interest rates and bought new home, upgraded their own homes, and even bought second and third homes. Being a real estate man, I long ago learned the bigger the property boom, the bigger the bust that always follows.

Last night on "60 Minutes," the Maestro (as Greenspan was often called) confessed that he had not realized until it was too late that the historically decreased interest rates would cause the credit crisis we have now. In his own words, Greenspan said, "I really didn't get it until very late in 2005 and 2006."

What Greenspan really failed to realize is that consumers as borrowers are human beings. And humans are full of emotions that often run in the way of logical decision making. Many Americans, even if they were comfortable with their homes, upgraded to bigger and better homes because reduced interest rates meant decreased monthly payments. Because of decreased interest rates, California and Florida are chock full of second homes consumers bought for vacation purposes. The developer made a fortune while the boom lasted.

Now, as interest rates have risen, consumers are having difficulties paying higher monthly payments. Property taxes have gone up, and so have utility costs. Cautious lenders are making it difficult for consumers to refinance and hence the bust phase for both real estate and lending is upon us.

Greenspan et al made a huge mistake in bringing interest rates down so much because such low rates simply induced millions of Americans to borrow more. It will be very interesting to see how the U.S. economy deals with "payback time" over the next couple of years. Personally, I believe the U.S. economy is entering a very difficult period.