K–12 computer science (CS) education can be transformed by infusing learning experiences with joy and creativity. This paper presents a qualitative study in which ten K–12 CS teachers submitted lesson plans exemplifying joyful learning. They then participated in in-depth interviews about their strategies and beliefs. Major themes from prior work include the role of joy in fostering engagement and creativity, the challenges posed by perceptions of CS as boring or inaccessible, and strategies for making learning personally meaningful and fun. We adopt perspectives from Flow Theory, Funds of Knowledge Theory, and Self-Determination Theory as a conceptual framework for our analysis. We draw conclusions regarding when teachers believe that joyful CS learning environments emerge and the discuss implications for designing CS curricula. The work elevates teacher voices and stories alongside academic analysis.