Just like the dating markets, a small shift at the margins can influence the culture quite a lot. You would not think that there would be much difference betwe

Just like the dating markets, a small shift at the margins can influence the culture quite a lot. You would not think that there would be much difference between a city with a 50-50 gender ratio and 52-48 (theoretically). But if you assumed that 80% of people are in relationships (1-1), and 20% are looking, suddenly that 4% difference turns into 33% more of one gender than another (hypothetically with 100 people, it would be 12 of one vs 8 of the other). So the culture between those two similar looking cities will be completely different. A similar thing happens with jobs. Going from 99% employed to 98% employed without changing number of jobs available can completely change the employment market dynamics overnight.