The Abilene Paradox
One of the interesting ideas explored in week 4 of Social Psychology is The Abilene Paradox. It is a paradoxical situation in which all members of a group (or organisation) collectively decide to pursue a course of action which, in reality, none of them wants to pursue. None of them knows that others also feel this way, and because everyone thinks that everyone else wants it, they all agree to the group decision in order not to be the sole opposing voice. In this way, the group decision runs counter to the individual preferences of all members.
The lecture contained a fun and entertaining educational video by CRM Learning explaining this paradox. Unfortunately that particular 2nd edition is not available for free outside Coursera (you can see the trailer here) but the first edition of the video with the same script can be viewed here. Alternatively you can read the classic 1988 paper by Jerry B. Harvey in which this concept was first proposed.