Interesting. Are there cultural differences wrt leaving visible footprints? do you need to feel private? is it ok to stare at other people, until they notice you? it can be very different between cultures.

I recently watched Ozu's "Good Morning" (1959) and was struck by the way people would come to a house, open the door, step in, and then call / announce themselves. Kids, relatives, neighbours, even a traveling salesman. I always assumed a closed house door invited people to knock and wait outside...