As you've no doubt noticed, companies and investors around the world are feeling the pain of China's economic slowdown. They're worried about all the layoffs, cuts to surplus capacity and deleveraging to come on the mainland, which will further depress demand. The natural temptation is to blame China for the world's woes. But outsiders should focus just as much on their own missteps -- starting with the widespread misperception that "this time" would be different.

Back in 2009, as China unleashed a massive fiscal stimulus and investment spree in response to the global financial crisis, the rest of the world was all too willing to believe the impossible. Aided byconsultant research predicting decades of explosive growth, companies placed huge bets on China and expected to ride the never-ending boom to riches.

Amid the gold rush, they bulked up to sell China t-shirts or tons of iron ore. They urged their governments to sign free-trade deals with Beijing. Commodity producers heedlessly expanded capacity, believing that 10 percent growth would continue indefinitely. Consumer brands rushed to set up flagships in third-tier Chinese cities. Shipping companies scrambled to build new fleets to meet an expected explosion in global trade.

However, as with so many previous bouts of irrational exuberance, this time wasn't really different. The ruthless rules of supply and demand still applied. And now, the longer that painful decisions are delayed, the harder they'll become. 

Commodities firms, in particular, are learning that lesson the hard way. As prices rose with Chinese demand, they made large upfront investments financed by borrowing -- often on a 20-year timeline, in the expectation that growth would last and last. Now, with China's economy slowing and the prices of everything from oil to metals plummeting, the bills are coming due.

David Fuller's view

All markets are prone to boom and bust cycles.  It is part of human psychology.  Many companies did extremely well participating in China’s boom years.  The most savvy of these knew in advance that they would overstay their welcome and this prepared them to cut back quickly when China eventually and inevitably slowed.  For commodity producers, expensive and lengthy lead times in production complicate the situation.  However, they are now cutting production and demand is increasing, including from China.