I like Shanghai.
It is a very modern and sophisticated city. A wide variety of lifestyle, from modern western, to Chinese middle class, from high-end luxury, to messy slum, from late night club, to comfortable reading club, mixed into this city. While glass-wall shopping mall and skyscraper flashes your eyes, your nose will also be struck by smells from the backyard of temporary wooden blocks, of course you may also find yourself walk into a small valley with elderly chit-chat or exercise surrounded by greens.
The public transportation is well-designed and very convenient, albeit I never had a chance to travel during peak hours or travel to some distance area yet.
You can meet people from everywhere. Local Shanghainese who mostly benefited from the fast development of the city with comfortable middle class lifestyle, business elites that have established their career during the past 10~15 years, well-educated “turtles” who find their ways to enjoy the same lifestyle as they used to overseas, ambitious young generation just entered the society still seeking the right balance for their own path, rural area families recently moved into the city hoping to achieve a better financial condition compare to their hometown, and of course foreigners who may or may not speak Chinese scattered themselves in different part of the city but often gathered in restaurants or bars that just like what they have at home.
You can find all kind of occasions that attract different people. Gym club, culture sharing, debates on freedom and government policy, entrepreneurship, concert and movie festivals, outdoor gathering and exercise, square dance, stall along the street, etc.