In business, too, the high times are often followed by an almighty headache. The original dot.com boom is often cited - as the money flocked online, young start-ups like Boo.com soaked up the accolades and lived it up with private jets and expensive champagne bashes, and no thought for the consequences. And one morning they awoke to find their entire business had gone down the toilet.
It has been party time in the business world again of late, and it's likely that the going could be about to get rougher. Still, how many of those currently flying high have actually planned for a downturn?
One of the few that did is Goldman Sachs. At the end of a blockbuster year in 2006, David Viniar, the CFO, realised the high times couldn't last for ever. So he took the decision to short the mortgage market to ease the pain of the comedown - the equivalent of downing a large glass of water before bed. And while its peers stumble about clutching their heads (or losing them, as in the case of Merrill Lynch and Citigroup, whose CEOs resigned last year), Goldman actually profited from the mortgage crisis and has continued its run of record results.
Knowing when to neck that metaphorical glass of water can be difficult. But if you keep an eye on the morning after, chances are your company won't be one of the many left reaching for the Alka-Seltzer.
Jennifer Harris is director of JRBH Strategy & Management, www.jrbh.co.uk.