Buying a home marks the true end of youthhood. You're ready to put down roots now, to establish yourself, to mark your territory. But have you seen what a modest house in a barely decent neighbourhood anywhere even remotely near a metropolitan area costs these days? There is no way you have anywhere near that much money, which means you have to borrow a lot, from the bank.
I'm not here to excuse homebuyers who have trouble paying their mortgages, but I think I can at least explain their thinking. The point is that while buying a house is quite clearly a momentous financial exercise, it is very much an emotional one, too.