In recent years, an increasing drumbeat around emotion research in ELT has brought to the fore an appreciation of teacher psychology and the emotional underpinnings of the teacher-student relationship. This study explores how students report their teacher's classroom behavior and how those observations lead learners to make broader impressions about the teacher's mental state. As part of a larger study, 129 adult EFL students took a web survey about their teacher's classroom behavior, perceived overall happiness, and their perceived wellbeing. Results revealed that teacher behavior was strongly correlated with perceived teacher wellbeing and happiness, meaning that based on how teachers behave in the classroom, students make far-reaching assumptions about their wellbeing beyond the classroom. Due to the phenomenon of emotional contagion, when students think their teachers are happy, they may also feel more positive emotions in the classroom. Suggestions for teachers are discussed, such as strategies for making the best of challenging situations and promoting healthy student relationships as a means to promote teacher and learner wellbeing. Suggestions for potential institutional changes are also made.