What did we learn from the financial crisis, the great recession, and the pathetic recovery?

This article comes in three parts. Part 1 reviews a few pertinent facts about the stunning economic events that have occurred in the United States (and elsewhere) since 2007. The author chose these particular facts from among many for their relevance to the rest of the article. The next two parts take up, first, some of the key lessons that professional economists should have learned from the crisis and its aftermath and second, some important lessons for teaching economics (especially but not exclusively macroeconomics). The two categories of lessons overlap a bit, but it is perhaps surprising how different they are.