Why do people think owning a house is a such a good idea?

Because home ownership has been the subject of a proganda barrage of advertising from various industries who want to maintain profit. Robert Kiyosaki calls a home a liability because it doesn't put money in your pocket, only takes it out. Contrast this with the typical dogma of your home being your greatest asset, which assumes that home prices never go down (clears throat) and that a home can be used as an ATM, ignoring the fact that just because you got $40k in your pocket from a refinance doesn't mean that this money is the same as earned income. You still have to pay that back.