Herding

Following what others are doing rather than acting on independent judgement.

Its professional form is career risk. A manager who is wrong alongside everyone else keeps their job; one who is wrong alone does not, which makes deviating from the consensus expensive regardless of whether it is correct.

The consequence at market level is that crowded positions become more crowded until they reverse, and the reversal is violent because everyone is on the same side.

Independent judgement is expensive precisely because it is rare.