And sure enough, the greed got seriously out of hand and then imploded, in fact twice, once with the bursting of the stock market bubble of 2000, and then even more seriously with the real estate and sub-prime mortgage bubble and resulting financial meltdown of 2008-2009.

FORBES: Bringing Back Glass-Steagall Would Rebuild Shattered Confidence In Wall Street

In the case of the U.S. economy now, the double-whammy of wealth shocks from the real-estate bubble and the stock-market crash has made consumers understandably cautious.

WSJ: Hal Varian: Boost Private Investment to Boost the Economy

If the real estate bubble bursts, it may produce a rerun of 2008, when the Shanghai stock market plunged about 60%.

FORBES: China's Coming Inflation Nightmare

Fearing a bubble, government officials have taken a myriad of steps to reign in the breakneck growth of the real estate market.

FORBES: China ETFs Navigate Tricky Housing Bubble

Critics point to a proliferation of ghost towns as evidence that China's real-estate market is a bubble that's bound to burst in a way that will badly damage the Chinese economy.

WSJ: China Pins Hopes on Public Housing

The real estate market, long considered to be a bubble even by some developers, is now the target of tough government measures intended to cool a speculative fever that has driven up prices dramatically in major cities.

FORBES: China Podcast: Former Billionaire on Trial & Real Estate Bubble