Our Own Worst Enemy

It has long been noted that investors - individual and institutional alike - tend to be their own worst enemies. They have an uncanny ability to buy stocks near market tops and sell near market bottoms. It's probably more accurate to reverse this implied causality. Markets top because the last investor in the herd has piled in, and markets bottom because the laggards of the herd has exited. 

​https://alphascientist.com/investor_flows.html