"Grades don't define you". You can be an engineer or a chemist and work in a university as a professor. In that case, you don't need to be a full-time teacher. Basically, teaching is imparting knowledge to an individual or to a group of learners of a specific subject. "Grades don't define you" is a famous quote for people who graduated with low remarks, yet excelling in the professional world. Teaching goes with passion and creativity. The learner's interest in learning the subject depends on how you present the topics to him. Most, if not all are unaware of it. As learning should be fun, so is teaching.