There are no long-term lessons - ever.

Bad things happen, but really bad things do not. Do buy the dips, especially the lowest quality securities when they come under pressure, because declines will quickly be reversed.

The inability to hold cash and the pressure to be fully invested at all times meant that when the plug was pulled out of the tub, all boats dropped as the water rushed down the drain.

Complexity - limits competition.

It is crucial in a sound investment process to search a mile wide than a mile deep with they find something - also.. never stop digging for information.

The government can always rescue the markets or interfere with contract law whenever it deems convenient with little or no apparent cost. (Investors believe this now and, worse still, the government believes it as well. We are probably doomed to a lasting legacy of government tampering with financial markets and the economy, which is likely to create the mother of all moral hazards. The government is blissfully unaware of the wisdom of Friedrich Hayek: "The curious task of economics is to demonstrate to men how little they really know about what they imagine they can design.")

Don't short many stocks. Instead they hedge for tail risk with CDS and options. They are happy to incur illiquidity