The purpose of this study is to examine how similarities between product designs manifest themselves in various aspects and how these influences purchasing and usage behavior. Product design similarity evokes positive images, such as a sense of security and familiarity, as well as negative images, such as mimicry and copying. For example, if you have just transferred to another school and your uniform does not match everyone else's, you might feel alienated. On the other hand, in parks and on street corners, wearing the same clothes and belongings can lead to an awkward moment. In the realm of psychology, the former is called the bandwagon effect and the latter is the snob effect. In contrast to the snob effect, which emphasizes scarcity, the bandwagon effect can create fads and hits. People experience both of these emotions, and it is said that using them appropriately and combining them leads to an effective marketing strategy.