And once fiscal credibility is established and a country has a low public debt-to-GDP ratio, the “automatic stabilizers” - which kick in to increase government spending to cushion the impact of difficult economic times - can operate without undermining the trust of citizens and investors. The third lesson we have all learned is the importance of being open to trade.
Finally, I think it fair to say that most central banks, faced with only a limited understanding of asset prices and their interactions with the full economy, engage in a form of risk management when dealing with market booms and busts.