Almost everyone in every group suffers from group-think. Even a group of rebels is just a smaller group of NPCs fighting a larger group of NPCs.
People who have original thoughts, or who can even contemplate ideas the people around them don't already share, are incredibly rare.
Very rare! That's what I like the most about the movie The Imitation Game. It shows the effort and work it takes to accomplish something unique that people don't understand! #filmstr 
That's where "team spirit" comes from. Everything that has *Spiritus*, that is: something that in-spires, something that lives and breathes (spirare) like a sports team, or a company, or a movement (why do you think we call it movement?) has an animating life force on its own, a _spirit_ that will animate and influence its members, who are in turn the constituents that bring said spirit about.
If you are completely and totally possessed by this spirit you turn into a predictable zombie. In other words, an NPC.
