If population growth continues unabated, I suspected that we will turn into rats. Apparently, rats kept in overcrowded conditions become stressed and violent. While rats do not have such added factors as human intelligence and compassion, they also lack human ego and vanity.
I am noticing an increased amount of territoriality, some conscious, some not. For example, when was looking for a table at a busy, upscale lunch place, I came across a woman who had bought a bottle of water and who, together with her bags, was spread across two tables and three chairs. This seems to be occurring more often—the need to sprawl.
Then there is the bus. High school students traveling 20 or 30 blocks require a minimum of three seats. Sometimes an entire seat is needed for a flung-out arm, which simultaneously embraces the adjoining seat and warns off anyone who might be considering using the seat portion. If the body posture doesn't deter you, perhaps the glaring, ice-cold expression will. (Neither is effective with me or my painful back.)
It's no better on the suburban trains. A couple of weeks ago, I entered a car that was half empty, but there was only one empty seat. Every other pair of seats was occupied by a VIP and his or her VIP baggage and/or body parts. As people boarded, no one budged.
Even public space has become something you claim, not share.