Yesterday at the grocery store I picked up a bunch of six bananas which were the proper color (due to ripen over the next 2-3 days), broke off four of them, and left two on the display. We can't eat six bananas in 3 days so I took only what I wanted.
I have always done this. I learned it from my mother, shopping with her as a young child.
However, this time for the first time ever, I saw the produce manager swoop in and remove the two green bananas from his display. He immediately took them to the back room. This explains why I can never find a "human-sized" cluster of bananas for sale in a grocery store -- it's always 6, 8, 10 bananas in a bunch.
It does not explain why produce managers do this.