The chart at the right shows two Mania Markets. The black line is the US stock market. Displayed over it in blue is the Japanese stock market, shifted forward 129 months. Both markets show a gradual rise in growth for many years. This is where the mania begins.
Prices then rise rapidly as the mania spreads like the flu.
Finally, the bubble bursts and prices drop sharply. After several years they level off. But they never return to their former glory days. The US has an entire generation of investors who do not understand this. Japan had such a generation, who are now wiser, humbler, and poorer.