As we all know, the key to successful investing is very simple: "Buy low, sell high." However, you enter a chaotic, fun-house world of uncertainty once you ponder the logical follow-up question: "When?" Investors desperate to solve this riddle have come up with solutions as varied as Fibonacci Analysis or the length of women's hemlines. At some point, most exasperated investors have even considered the strategy articulated by Seinfeld character George Costanza: "If every instinct you have is wrong, then the opposite would have to be right."
Source : dshort.com