A critical incident is any unplanned event that occurs during class. In has been suggested that if trainee teachers formally reflect on these critical incidents, it may be possible for them to uncover new understandings of the teaching and learning process. This paper outlines and discusses how eighteen trainee teachers in an English language teacher education course in Singapore reflected on critical incidents that occurred while they were teaching. Results indicate that while analysing critical incidents can be useful for trainee teachers, language teacher educators should realize that classification of such incidents into neat categories may be problematic and that care should be taken when assigning a critical incident assignment.