One important consequence was a housing boom in the United States, a boom that was fueled in large part by a rapid expansion of mortgage lending. Unfortunately, much of this lending was poorly done, involving, for example, little or no down payment by the borrower or insufficient consideration by the lender of the borrower's ability to make the monthly payments.
Lenders may have become careless because they, like many people at the time, expected that house prices would continue to rise – thereby allowing borrowers to build up equity in their homes – and that credit would remain easily available, so that borrowers would be able to refinance if necessary.