Ignorance of others causes stress
Ignorance is completely bliss. Not thinking would be a ducking dream for most of us. The ignorance of OTHERS causes stress. The only logical solution to this type of stress is to ignore it.
Native American architecture and cultural history shows that no matter the size of the Tribe, privacy did not exist. Privacy meant Outcast.
Privacy is a white-European notion. What happens when we run out of room for privacy on this blue ball? We'll need to evolve...