Inspired by the investigative and pedagogic approach of Exploratory Practice (Allwright, 2003), this study aims at understanding why the 1701 class feels happy during their classes of English as a foreign language, in the 7th grade of a municipal school in Rio de Janeiro, Brazil. In this participatory practitioner research, the teacher-researcher and the learners in one of her English classes work to understand the quality of classroom life that they co-construct during their pleasant pedagogic interaction. The research was carried out through a pedagogic activity with exploratory potential. This work for understanding searched for the understandings of all the participants regarding the quality of their classroom teaching-learning experience. The analysis of the exploratory discourse produced by the students and the teacher’s reflective narrative of her personal professional experience was based on Bakhtin’s (2003) notions of historicity, dialogism, utterance and voice as well as the notion of affect, as discussed by Arnold & Brown (1999) and Allwright & Bailey (1991). The understandings reached by the teacher-researcher about her professional experiences and the reflexive analysis developed in this study suggest that the 1701 class is a space shared by people with different knowings and pedagogical beliefs, who echo demonstrations of affect. The quality of this group’s enjoyable classroom life appears to be co-constructed through the Good-mornings! shared in the beginning of their classes, through the teacher’s personal characteristics and knowledge-base, through the socio-affective relations established among the people in the classroom, and through the cognitive processes developed.