Designers' promises or users' expectations?

Several frameworks describe the design process, such as the FBS model and its extensions. Some of them present a designer-centric view, while the most recent ones are more based on the user's point of view. This paper investigates and seeks to explain the different perspectives between designer and user after the first interactions with the product. In particular, the paper models how the designer's promises of functionalities match (or mismatch) the user's expectations. Thus twenty-four examples, including misuses, unperceived functions, hidden functions, failures etc., are mapped in a table. The paper provides also a formal model based on Function-Behavior-Structure approach to describe the possible cases of misunderstanding between the user and the designer. Such a model formally links the designed product, as it is conceived by the designer, and the perceived product, as it is understood and interpreted by the user. Finally a series of redesigned actions are proposed to try to overcome some of the cases of misunderstanding between the user's and the designer's perspectives.