If you are a man with great ambition, but have achieved nothing in your career and only have an average income, then it's better to leave Shanghai as soon as possible. Otherwise, many years later, you will end up with nothing and just become a sacrifice to this city. This city will ruthlessly abandon you after sucking all the热血 (enthusiasm/blood) out of you. It gains prosperity, while what you lose is your youth.
If you are an elegant woman, but still haven't found the place where you belong, it's better to leave Shanghai as early as possible. The skyscrapers in Lujiazui cannot support your dreams, and the繁华 (prosperity/noisy prosperity) of Xujiahui cannot provide you with a happy life. This city will kick you away after trampling on your originally pure body. What it gains is pleasure, what is shattered is your dream.