Summary: The human-machine interaction maybe perceived by the user as simple operation in wait of results predefined (to send a message, to call somebody, to download a video) or as process, art to make, adjustment between the user and the interface. In this last case, the interaction is less lived as an operation than as a dynamic cooperation between the user and the machine. This second meaning of a word, which engages the user as sensitive subject more than as pragmatic subject raises the following question: what is the pleasure of the interaction between the user and the machine? From a corpus of digital objects’ interfaces (mobile phones, Pda, communicating objects, video games), we shall specify how the digital objects, via the various sensitive forms which underlie their interface, promise a pleasure of interaction based on different and specific value systems.