Bubbles burst and people get hurt. That's what happened in Ireland, Spain and the United States through the global financial crisis when house prices fell by between 30 and 50 per cent.
But is a bubble forming in New Zealand - or, rather, Auckland - and, if it is, could the end result be ugly here?
For answers to those questions, Property Report talked to economist Rodney Dickens (pictured), an expert in residential real estate and a former ASB Bank head of research.
Dickens sees a bubble as "a somewhat vague concept".
"I think about it in terms of the yield on the asset," he says. "A sure sign of a bubble is when price increases result in really low rental yields that are not justified by other things.