Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Why is being “upside down” on a mortgage so bad?
The problem comes when the borrower cannot afford his home.  If a borrower buys more home than they can afford, as long as he can sell the house for more than he owes, he's not in a disastrous situation. He can sell the house, pay off the mortgage, and choose more affordable housing instead.  If he is upside-down on his home, he doesn't have that option. He's stuck in his home. If he sells it, he will have to come up with extra money to pay off the mortgage (which he doesn't have, because he is in a home he can't afford). It used to be commonplace for banks to issue mortgages for 100% of the value of the home. As long as the home keeps appreciating, everybody is happy. But if the house drops in value and the homeowner finds himself unable to make house payments, both the homeowner and the bank are at risk. Recent regulations in the U.S. have made no-down-payment mortgages less common.