if interest rates spike.
Its an odd situation, because most homes are locked into rates now, instead of ARMs. So if rates do spike, it doesn't make the home you're in less affordable. But it does, potentially, make it un-sellable near what you paid for it. So you're stuck with it with potentially no equity even if you've put 20% in.
You could lease it if you needed to move, but otherwise you're toast.
Pondering this kind of scenario really makes me want to sell and go lease for a couple years, buy property and then build when the market cools. The question is, will the Fed ever let rates rise again, or will it do whatever necessary to keep rates low?