This study explored three retired teachers’ “personal theories”. It aims to analyze the “personal theories” formed by these retired teachers and the similarities of their life stories. The study discovered teachers’ deep thinking mainly via interviews. This study obtained results as follows: 1. The similarities of their life stories include: the characteristics to be a good teacher, a sense of mission developed by teacher education in early years, the participation in professional communities bringing sharing stages, and autonomy gained through the educational reform. 2. The common traits of these teachers’ personal theories include: “Holistic concern and positive thinking”, “Transforming from a strict teacher to a brilliant one”, and “Reflection in act, and transforming knowledge into wisdom.