Comedy has long been analysed from a pragmatic perspective with the predictable conclusion that we laugh because one of the four Gricean maxims has been violated. However, the wording of Grice’s maxims is so loose and flexible that more or less any joke would violate one of his maxims and thus the ‘Cooperative Principle’. So, we are still left mediating the meta-pragmatic question of what it is that lies behind verbal incongruity that makes us actually laugh? This article analyses the notion of incongruity from a Peircean semiotic perspective and focuses exclusively on a selection of British comedy duo sketches whose humour is derived overwhelmingly from discursive, lexical and socio-phonetic incongruity. On the basis of classic British comedy due sketches at least, there is some mileage in perceiving incongruity as a semiotic misalignment or ‘indexical shock’ which subverts our basic social expectations by indexing non-presupposed contexts. We laugh because our verbal norms are not only challenged, but are turned upside down and torn apart. Moreover, we laugh because the social identities that the speech acts aim to index non-referentially often clash or conflict immediately with those of his or her interlocutor’s.