Because first of all, people have become open from the original conservative consumption concept, and understand today's phone bill and tomorrow's money. In addition, it is increasingly difficult to earn money in society, but people's material and spiritual needs are getting higher and higher. In order to meet these needs, many people can only borrow money. Then there is the issue of national policy. The national macro-control guided people to encourage consumption in advance, so they let go and formulated a series of loose monetary policies to make loans easier. There are more and more ways to make money, so many people seize the loophole of credit card overdraft loan to complete the performance amount and the law of fund movement back and forth to complete their work and get paid.