In 2000, the Dow Jones Industrial Average was at record heights, with tech companies trading at valuations that made you think the old rules of finance no longer applied. If Cisco (Nasdaq: CSCO) kept up with analyst growth projections, it would have eventually grown larger than the U.S. economy.

The world was different, people said. Recessions were a thing of the past. Technology would create limitless prosperity. The stock market wasn't a bubble. It was reflecting the new reality.

Yale economist Robert Shiller didn't buy it. He wrote a book, Irrational Exuberance, explaining why there was no way to justify valuations.

That was his first win.

Five years later, real estate was the new boom. Since land was a limited resource, prices could only go up, people said. And since housing was a leveraged investment, it was an easy road to huge wealth.

Again, Shiller didn't buy it. Again, he wrote a book about it, explaining why prices were way too high.

That was win No. 2.

How do you stand apart from the crowd and see things others don't? I asked Professor Shiller in an exclusive interview last month. Have a look: