Working with Korean university-level learners of English, this study provides a detailed analytical comparison of 2 task work groups that were video-recorded, with 1 group scoring very high and the other relatively low based on the results of a Group Work Dynamic (GWD) measuring instrument. Adopting a complexity theory (CT) perspective and utilizing what Dörnyei (2014) has termed a retrodictive qualitative modeling (RQM) approach to research, the study sought to identify how various elements interacted to influence the emerging GWD patterns. Based on different layers of data from the GWD measuring instrument, affect-related state questionnaires, interviews, and extracts from the transcribed interaction, the signature dynamics for a strong and weak GWD related to a combination of (a) positive and negative GWD behaviors, (b) affect-related states in the form of motivation, emotional state, and perceived difficulty, (c) critical moments in the interaction, and (d) the system's initial conditions, which were characterized by specific task characteristics and the learners' affective states just prior to beginning the task. Acting as key control parameters in the shaping of GWD outcomes were task conditions associated with the use of imagination, planning time, humorous content, difficulty level, and multiple task outcomes.