Most investors eventually fall into the same trap, because calling the top feels far more rewarding than following the trend. Once valuations become stretched, social media fills with charts comparing today's market to past bubbles, while every new high convinces more people that a crash must be just around the corner. The problem is that expensive markets can keep getting more expensive for much longer than most investors expect.
One remark captured that reality better than any prediction about China or the US: "I'm a value guy. I don't love the US market... but I sure as heck won't be short." Anyone who has lived through several market cycles knows how quickly liquidity can overpower valuation, especially when central banks around the world are cutting rates and governments are adding stimulus at the same time.
Shorting an overvalued market during a global easing cycle often becomes a test of patience that few investors can afford to pass. The thesis may eventually prove correct, although margin calls, borrowing costs and months of rising prices have a way of ending the trade long before the market changes direction.