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.
The Housing Lab 