It has become commonplace to ask, whenever anything has gone wrong, what lessons can be learned from the experience. But the appearance of open-endedness in that question is misleading: not every answer that we could give to it is acceptable. There are, in the context of such a question, tacit constraints in what counts as a valid lesson to be learned. The article considers what these constraints might be and the different kinds of lessons one might learn from experience, which the common way of taking the question ignores. Initially I attempt to distinguish between lessons that have to do with action and those that have to do with understanding; between lessons that are about the results of our actions and those that are about the meaning of actions and events. On closer examination, however, these distinctions are seen to break down; to represent a difference of degree rather than of kind. In the latter part of the article, therefore, I find the crucial distinction to be between lessons that we can apply, while being ourselves unchanged, and lessons which, by changing the way in which we see and respond to people and events, re-constitute our selves and thus express themselves through us willy-nilly in our subsequent thoughts, words and actions.