This article is an attempt to bridge the divide between academics and practitioners. Informed by both design theory and the reality of policy work, its focus is on ‘problems’. From a practitioners’ perspective, policy design is both an intellectual and political process, an inevitable oscillation between ‘puzzling’ and ‘powering’, in which ‘messy’ or unstructured problems are re-structured from problems as webs of ‘undesirable situations’ to problems as specific, time-and-space bound ‘opportunities for improvement’. This requires a questioning habitus in practitioners of policy design. Using a socio-cognitive theory of problem processing, this paper shows how policy design is an iterative process of problem sensing, problem categorization, problem decomposition and problem definition. For each of these stages, appropriate rules-of-thumb for questioning and answering can be suggested that induce thought habits and styles for responsive and solid policy designs.