In a culture which places increasing emphasis on happiness and wellbeing, multimedia technologies include emotional design to improve commercial edge. This chapter explores affective computing and illustrates how innovative technologies are capable of emotional recognition and display. Research in this domain has emphasised solving the technical difficulties involved, through the design of ever more complex recognition algorithms. But fundamental questions about the use of such technology remain neglected. Can it really improve human-computer interaction? For which types of application is it suitable? How is it best implemented? What ethical considerations are there? We review this field and discuss the need for user-centred design. We describe and give evidence from a study that explores some of the user issues in affective computing.