Cities are a natural progression of human population growth and progress:

Where ever there has been a rapid growth of population powered by agriculture, animal farming or industry, there has been rise of the city.

Cities are a more efficient way of packing in people:

Studies have shown that per capita utilization of resources is more efficient in cities. This is a necessity. Systems evolve for this. Better sanitation, better water distribution systems etc.

Cities enable more specialisation, more trade, and more progress of technology- faster.

Cities allow for more specialists. A paediatric neuro endocrinologist or a hydraulic systems consultant can survive in a city. An impressionist painter has to come to a city to be appreciated. This is the primary reason why cities grow. That is where the jobs are. Systems get perfected here. Trade flourishes because of production by specialists and distribution by systems.

Cities have a tendency to have secular values and discourage group fights:

This is because everyone is part of the system. Co-operation is necessary for survival.

On the flip side, there is more stress:

Human beings are evolved to live in small closely knit tribes, with relatives around. Cities are too crowded, noisy and impersonal. Average blood pressure is 5 to 10 points higher among city dwellers and psychiatric illnesses are commoner. Crime is more rampant as there is the protection of anonymity for criminals. Good systems of security and policing are imperative.

But better get used to them. Cities are here to stay. And grow.