An established body of literature shows that a student's affect can be linked to her epistemological stance . In this literature, the epistemology is generally taken as a belief or stance toward a discipline, and the affective stance applies broadly to a discipline or classroom culture. A second, emerging line of research, however, shows that a student in a given discipline can shift between multiple locally coherent epistemological stances . To begin uniting these two bodies of literature, toward the long-term goal of incorporating affect into fine-grained models of in-the-moment cognitive dynamics, we present a case study of "Judy", an undergraduate engineering major. We argue that a fine-grained aspect of Judy's affect, her annoyance at a particular kind of homework problem, stabilizes a context-dependent epistemological stance she displays, about an unbridgeable gulf she perceives to exist between real and ideal circuits.