In her 2017 show Nanette, Australian comedian Hannah Gadsby announced that she was quitting comedy. In the show, Gadsby argued that as a marginalized person – a gender-nonconforming lesbian from rural Tasmania – she was doing herself a disservice when she invited audiences to laugh at her trademark self-deprecating humour. Gadsby framed her decision to quit comedy partly as a problem of persona: her practice as a comedian was to take actual, sometimes traumatic, events from her life and turn them into jokes, which she described as ‘half-told stories’. So framed, the problem with Gadsby's comic persona is the way it both presents and truncates her traumatic experience. When she refuses to be funny, Gadsby casts herself as something like Sara Ahmed's ‘feminist killjoy’, a spoilsport figure whose unhappiness positions her as a source of tension. In this article I consider how Gadsby's decision to quit comedy, and the terms in which she articulates that decision in Nanette, can help us think about varied modes of humourlessness and comic possibility.