In recent years, the deteriorations of living habits like immobilization or unhealthy diet are becoming serious social problems in many developed countries. Even if we know the importance, it is difficult to change our undesirable habits and to maintain a desirable lifestyle. Previous studies have suggested that persuasive technology can play a significant role in persuading individuals for behavioural change. In the article, we discuss the design of persuasive ambient displays aimed at addressing this issue borrowing theories from behavioural psychology. In our design, aesthetic and empathetic expressions are used to represent the visualisation reflecting behavioural feedback of an individual. If an individual's behaviour is leaned towards healthier lifestyle, the display expression is designed to boost his/her positive emotion where as display expression is progressively shifted to increase negative emotion of the individual if he/she does not sustain the desirable behaviour. In this paper, we introduce design principles of our approach and present four case studies to show the applicability of our approach. We also discuss a number of issues uncovered during the design and evaluation of these case studies.