Since I've lived in New York, I see a lot of self-segregation based on skin color, ethnicity, religion, etc. (My heart breaks every time I hear someone use the phrase "my people") My husband's family, who's black has lived for years next to a Jewish family. While they always had been cordial to each other, there was always an emotional distance between them. One day, my DMIL noticed the Jewish husband outside with no coat in the middle of winter. He had taken the garbage out, and locked himself out of the house. She opened the door and told him he could wait in her house until his wife came home. He refused. Well, she pulled out her "Mom voice" and said, "I don't care if this isn't a Jewish house, you're coming in here to wait for your wife!" And he did. These two families have been dear friends ever since.