"But the overwhelming majority of homeowners are doing just fine. So how is it that a mess concentrated in one part of the mortgage business — subprime loans — has frozen the credit markets, sent stock markets gyrating, caused the collapse of Bear Stearns, left the economy on the brink of the worst recession in a generation and forced the Federal Reserve to take its boldest action since the Depression?" -- The New York Times
Look at it this way. The overwhelming majority of football players are doing just fine. So how is it that a late score in one football game could ruin so many problem gamblers?
A bad bet on a football game can cost you much more than the price of the ball.
A lot of the money in the economy is riding on bets. They're complicated bets that a lot of people don't understand, but in simple terms, they're just bets.
That shouldn't be so hard to understand.