The "enhancement agenda" in educational policy is based on the idea that "something affective", which supports and improves learning, can be a) measured and b) enhanced. This idea is explored, and it is argued that the identity of the "something" that the enhancement agenda seeks to enhance is fatally obscure, as is the idea of measurable enhancement. Interpreted in Aristotelian terms as the desire to cultivate certain emotional dispositions, the idea of "prevailing" on children morally makes good sense. Unlike the enhancement agenda, however, the Aristotelian project is informal, intimate and bound to the notion of human flourishing. The paper concludes with an enquiry into the central concerns that drive the enhancement debate, and an answer is sketched in terms of excessive fear and shame, and the circular logic of failure. This answer, it is argued, elucidates an "ordinary" concept of low self-esteem that is a potential "barrier to learning", and should therefore be taken seriously by educators.