(This post was inspired by a post by ledrakenoir.)
I heard this back when I was in school in the 1970’s.
A group of psychologists had a person lie down and pretend to be unconscious in the middle of a street. Then they observed the reactions of people passing by. The experiment was carried out in a large city and in a small village.
In the city, people would walk around the “unconscious” person, or right over them, but very few would stop to offer help. After all, there are more than a million people in Copenhagen (assuming it was in Denmark, where Copenhagen is the only real city), so somebody else would probably take action.
In the village on the other hand, the first person to notice the “unconscious” person would rush to their aid! You couldn’t expect somebody else to handle the situation for you (and I also suspect another motive: If you ignored a sick person lying in the street, the neighbors might notice you ignoring the person! ;)).
Conclusion: If you want to be left alone, move to a city where even people living in the same stairs will (pretend to) not know you. In a small village, where everybody knows everybody else, you won’t be left alone.
(Another study I heard of once found that, if there are more than three stories to a block of flats, people stop greeting each other when they meet on the stairs. I don’t think I could ever live in a large city.)