Previous waves of Chinese immigrants to Hong Kong came mostly from the southern part of the country. They often spoke Cantonese and integrated quickly. But the latest influx comes from all over the mainland, says Eric Fong of the University of Hong Kong. “Integration, if it occurs, may take longer than in the past.” Hong Kongers, protective of their distinct identity, are not always the most welcoming bunch. When a group of mainland children was spotted squatting on a train platform last year (as is customary in parts of China), locals poked fun at them on social media.

Some aspects of culture are really not worth defending. Another big L for the economist.