In a big city, people can take the chaces to study and work best. There are many good University for u to choose in a big city. There you can express your ability to study what you like. Moreover, when you graduate, you also find it easier to find chances to get a good job with good salary, that is quite difficult in small cities or countrysides; because there concentrates many big companies and groups. Hence, many graduate students choose big cities to live and work. In short, it is where you can take advantages f yourself.
In addition, in a big city you can enjoy the best service and entertainment. Because there are many rich people here, they can invest much money to get the best for them. Lives in a big city are quite luxurius but you don't have to be worried when you are sick or suffer a disease because there you can find good doctors for you, as long as you have muich money. What's more, in a big city you can enjoy new entertainment such as new games or luxury games. Many people can argue that living in a big city makes them tired with noise and dash. They like the slow pace of life in a countryside. But I think that you can live there for a long ime because the young always like to enjoy new things and want to have much money, which is very difficult to do in a countryside. However, when you get older, especially when you retire, a countryside wll the best choice to live.
In summary, living in a big city has many advantages. However, you have to try your best to overcome all difficulties such as hard competition in workplace or polluted environment.