The thing about financial crisis is that they are not predictable, not in terms of occurrence, intensity nor duration. They usually blind side you, because if conditions leading to a crisis were obvious then market activity on its own would avert it.

In other words, if a stock bubble was obvious to everyone, arbitrage traders and short sellers would pop it on their own.

Sometimes a crisis seems obvious in retrospect, but upon more detailed observation that is not really so. In 2008, for example, it seemed obvious that the housing market was way over valued to a lot of people who didn't have a direct stake in housing and related securities, but it wasn't the collapse of real estate values that sank the economy. It was the crisis in confidence following the failure of Lehman Brothers, and the recognition that many AAA-rates mortgage backed securities and derivatives were probably worthless, that turned the bust of the housing market into a global catastrophe. The overvaluation of the housing market was obvious and somewhat predictable. The contagion of fear following the collapse of Lehman was not.