Application-centric computing dominates human-computer interactions, yet the concept of an application is ambiguous and the impact of its ubiquity underexplored. We unpack "the application" through the lens of non-standard knowledge work: freelance, self-employed, and fixed-term contract workers who create knowledge in collaboration with a wide variety of stakeholders on a per-project basis. Based on interviews with fourteen participants we describe how: i) their economic value is intertwined with data and skills related to specific applications; ii) their access to this value is systematically jeopardised in collaboration due to the different application practices, preferences, and proficiencies of other stakeholders; and iii) they mitigate the costs of this compromise through cross-application collaboration strategies. We trace these experiences to common characteristics of applications, such as update processes, interface symmetries, application-document relationships, and operating system and hardware dependencies. By empirically and analytically focusing on "the application", we reveal the implications of the current application-centric computing paradigm and discuss how variations within this model create qualitatively different human-computer interactions.