Sustainable technology is a microcosm that illuminates the relationship between technology and human agency. We tend to think about sustainability in terms of the properties of things. However, technology is not just things but techniques which have their own bearing on sustainability, for users may employ sustainable technologies in unsustainable ways. Clueless or stymied users may be managed through education or redesign; however, there are intractable users who cannot be managed through either approach. I trace the cause of this intractability to interaction between the improvisational nature of human agency and the multiple realizability of artifact functions. I argue that managing intractable users requires going with the flow of their relationship to technology rather than trying to control it through education or redesign, and that democratizing the development and distribution of technology is the best way to do this. Finally, these results easily generalize to technologies not aimed at sustainability.