Despite the growing importance of sustainability and the sustainable development agenda, and despite the growing presence of papers recognising the critical interaction between sustainability and accounting and finance (and, indeed, with all social science), there has been a relatively muted response apparent within the accounting education literature itself. This relative lack of literature may well be unexpected but what is not unexpected is the difficulty that accounting and finance teachers have in developing such demanding new ideas with accounting and finance students in the classroom. Without in any sense gainsaying the considerable impediments to innovation, this explicitly polemical essay seeks to address a more fundamental difficulty: that of the way in which sustainability is approached and represented in both the literature and the classroom itself. The contention is that, unless sustainability is "keeping you awake at night", you do not understand it. The paper seeks to support this contention and then offers an example of one undergraduate course that is explicitly designed to stop students sleeping peacefully.