It is often assumed that the interests of users and developers coincide, sharing a common goal of good design. Yet users often desire functionality that goes beyond what designers, and the organisations they work in, are willing to supply. Analysing online forums, complemented with interviews, we document how users, hackers and software developers worked together to discover and apply system exploits in hardware and software. We cover four cases: users of CPAP breathing assistance machines getting access to their own sleep data, 'hacking' the Nintendo switch game console to run non-authorised software, end-users building their own insulin supply system, and farmers repairing their own agriculture equipment against suppliers terms and conditions. We propose the concept of the 'gulf of interests' to understand how differing interests can create conflicts between end-users, designers, and the organisations they work in. This points us in the direction of researching further the political and economic situations of technology development and use.