A flock of starlings turns as one because every bird is reading the handful of birds nearest to it. People work the same way. We pick up the mood of whoever we spend our days with, and they pick up ours. Camp puts everyone in close quarters for eight weeks, which makes the effect stronger there than almost anywhere else I have worked.
This is the short version. The full lesson, with the story behind it, is in the book.
Take The Summer Camp MBA with you, or get the field notes by email while you work through the lessons here.