From Howard Marks in his memo "
On the Couch":
One of the most notable behavioral traits among investors is their tendency to overlook negatives or understate their significance for a while, and then eventually to capitulate and overreact to them on the downside. I attribute a lot of this to psychological failings and the rest to the inability to appreciate the true significance of events.
As negatives accumulate – whether they surface for the first time or just are finally recognized as significant – eventually a time comes when they can no longer be ignored, and instead they come to be treated as being of overwhelming importance.