What motivates research-focused academics, employed at a leading research university, to want to teach well--particularly considering that many of them admit to prioritising research above teaching? Why do they not simply settle for expending as little time as possible on their teaching planning and preparation, delivering run-of-the-mill, lack-lustre seminars and lectures that fail to inspire their students? These are the central questions addressed in this article, which revisits and re-analyses data from a 1993-4 case study of teaching and learning in a UK research-intensive university. Selected qualitative data from the original study are used to present an overview of the attitudes toward teaching of, and the teaching approaches used by, eighteen academics, and these data are supplemented by up-to-date follow-up data gathered in 2009. The picture is one of effective--often innovative--teaching carried out conscientiously. Yet the teachers are, by their own admission, first and foremost researchers. What, then, motivates their teaching? Applying what we call "feasibility-determined analysis", we hypothesise that the academics were motivated by self-esteem needs, which, in turn, were fed by self-efficacy beliefs and the pursuit of a sense of achievement. Finally, we briefly discuss the wider implications of this hypothesis for professional development in higher education contexts.