Regret is a slippery phenomenon. Fundamental questions about its fittingness conditions and functions have yet to be settled. Here, I offer a diagnosis of regret’s slippery character. Extending a suggestion made by Daniel Kahneman, I argue that regret comes in a range of emotional flavours, distinguished in the first instance by their phenomenology. While regret has received some attention from philosophers, its varied phenomenology has not been investigated. Yet the varied phenomenology of regret is significant: it reflects further variations in (...) its cognitive and motivational effects. As a result, I argue, different flavours of regret have different fittingness conditions and contribute to our lives in different ways. In Section I, I offer a preliminary sketch of regret and introduce the questions that drive my discussion. In Section II, I introduce regret’s different flavours. In Section III, I investigate their contrasting cognitive and motivational effects, with a view to determining their functions. In Section IV, I investigate what this implies concerning regret’s fittingness conditions—and, in particular, what constitutes a regrettable action. (shrink)