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.