The 100% solution: what is a user to do, and how are we helping?

We deploy our applications for use in worlds that change, and in places not anticipated by their designers. As a result, our applications do not - and, in principle, cannot - anticipate all the circumstances in which they are used. Yet the user must cope with every single circumstance that they confront, and they must find some way to bring the application to bear on those situations. I explore some thoughts and challenges concerning the resulting inevitable misalignment between the user's needs and the application's capabilities. I explore three kinds of solutions: fixes (changing the application), work-arounds (going "outside" the application), and appropriations (going to school on other cases). The resulting socio-technical systems (humans and applications working together) can address circumstances unanticipated by the applications. I argue that the implication for designers is that we must challenge ourselves to design applications that support, not only the circumstances that we anticipate, but also the systems that people adopt for dealing with circumstances that we have not anticipated. I close by speculating on reasons why we have not yet focused on this issue.