Young couples often buy houses that are really more then they can afford now, on the theory that in the decades they will spend paying it off their income will go up.
That idea has been really dangerous though in the past decade or so as jobs have become less stable and pay raises smaller. Back in the 60s and 70s people expected to get a pay raise every year that was larger then inflation.
What I find amazing is how often people with no savings and large debts can get that kind of financing. I know people that have used financing to get money to pay the downpayment on their house, something that banks used to never accept.
Jay