Addiction is human nature. We are more likely to achieve commercial success by making addictive products. Whether you are an entrepreneur or an investor, the "addiction" attribute is a core point you need to pay attention to when choosing a project. We divide users into five levels according to the intensity of their demand for products. The first level is "addiction", the second level is "reducing pain", the third level is "increasing happiness", the fourth level is "basic needs", and the fifth level is "pseudo needs".