Robert Shiller, the co-creator of the S&P Case-Shiller Index, which tracks national housing prices, is a man that has earned a great deal of respect for his knowledge of the real estate market. Yet he is still guilty of saying the silliest of things.
For instance, the other day he said, "There could be another bubble...people have gotten very speculative in their attitudes toward housing."

To be fair, Shiller qualified his statement by saying he doesn't think another housing bubble is likely, or will happen soon. Nevertheless, that isn't how bubbles work.