Remember 2007? Glory days, right? Everything was booming, and nothing was booming quite as much as real estate — especially commercial real estate. Malls, hotels, warehouses, industrial parks: Everything was being built, and everything was being financed on ridiculously generous terms. Remember interest-only loans? Good times. But commercial real estate is different from residential in one important way: Your standard residential mortgage goes 20 to 30 years. Your standard commercial loan goes for five years, at the end of which you either make a big balloon payment (what it is that balloons remind me of?) or you refinance, the idea...