Why does Goffman emphasize the importance of presentation of self in everyday life

Why does Goffman emphasize the importance of presentation of self in everyday life? Which perspective(s) is/are best reflected in this work? How is this work important for the symbolic interactionist perspective? Why is this work considered so important for dramaturgical analysis? How can you use the concepts in presentation of self in everyday life in your everyday life? How has modern technology (e.g., social media) changed how we present ourselves in everyday life.

The Presentation of Self in Everyday Life
Book by Erving Goffman