The document discusses the reasons why the author chose to become a Mandarin teacher. There are two main reasons: 1) the growing popularity and demand for Mandarin teachers worldwide as Mandarin has over 100 million speakers and 350,000 students studying in Chinese universities, and 2) teaching has always been the author's passion as they love helping students learn and experiencing different cultures. The author finds teaching rewarding as they were able to help one student advance significantly in their Chinese proficiency. They also feel they have gained valuable experience and learned from their students over their two years of teaching so far.