For US stock markets, last week was the worst start to a year EVER. And lots of other countries were hit even harder. What happened? In two words, debt and China. We've borrowed way too much money in the past few decades, so a crisis was long overdue. And China's myriad mistakes are now impacting the rest of the world. Toss in a eurozone political crisis and Middle-East war, and as goes January, so might go the rest of 2016.