Irrational exuberance Pink also used the phrase in 2009 in his book "" in the chapter discussing how extrinsic motivation can encourage short-term thinking at the cost of long-term health: "This is the nature of economic bubbles: What seems to be irrational exuberance is ultimately a bad case of extrinsically motivated myopia". Irrational exuberance "Irrational exuberance" is a phrase used by the then-Federal Reserve Board chairman, Alan Greenspan, in a speech given at the American Enterprise Institute during the dot-com bubble of the 1990s. The phrase was interpreted as a warning that the market might be overvalued. Greenspan's comment was made during
Greed and fear Greed and fear Greed and fear refer to two opposing emotional states theorized as factors causing the unpredictability and volatility of the stock market, and irrational market behavior inconsistent with the efficient-market hypothesis. Greed and fear relate to an old Wall Street saying: “financial markets are driven by two powerful emotions – greed and fear.” Greed and fear are among the animal spirits that Keynes identified as profoundly affecting economies and markets. Warren Buffett found an investing rule in acting contrary to such prevailing moods, advising that the timing of buying or selling stocks should be "fearful when others are