Abortive humour can be accounted by communicative gaps, at semantic or pragmatic levels, but at times people oppose humour for just discursive causes (e.g. defective literacy ability, literacy skill). Hence humour reception is more intricate than it seems. This paper states that there is a ‘default setting’ in persons’ discourse, such that when meeting humour, they all use a discursive defence mechanism (DDM), and that there are ‘triggers’ which induce this DDM.