This essay argues that there are educational situations in which interlocutionary misbehaviour in the form of withholding ‘good will’ can have educational value. It describes an exchange between a teacher and a student in which the teacher withheld good will, and analyzes this exchange through conceptual frameworks of performative contradiction and differend, provided by Derrida and Lyotard, respectively. It further analyzes how context, power, and ethical considerations affect the evaluation of instances of interlocutionary misbehaviour. The essay ends with the ironic (...) observation that even in cases in which refusing to extend good will to one's interlocutor is educationally pertinent, good will is not absent from the exchange altogether. (shrink)