Why are people building gigantic houses? Up to a certain point, they think that they want a large house, but a lot of people I talk to are looking for a house in a specific price range. When I ask why they want to spend that much on a home the answer is always the same: the Mortgage Interest Tax Deduction. There are several good reasons for this deduction to exist, but Mansions & McMansions are definitely not a good reason. This article details a very intelligent way that the government could change this program so that it helps more of the people who need it the most while closing the mansion loophole.