Emotion refers to seven emotions such as joy, anger, worry, thinking, sadness, surprise and fear. The change of everything has a dual nature, which can be beneficial or harmful to people. Similarly, people's emotions and emotional changes have both advantages and disadvantages. For example, it is said in the Record of Nourishing and Prolonging Life that "moodiness is harmful." "Three causes and one disease syndrome" officially lists joy, anger, worry, thinking, sadness, fear and shock as the internal causes of the disease.