One obvious challenge for affective interfaces is to find ways of checking whether the expressed emotions are understood by users, and whether the sys-tem can interpret user emotions correctly. Even more challenging is whether the overall usage scenarios are achieving their purpose of being e g engaging, fun, believable, or creating a relationship with the user, and how much of this can be attributed to the emotion modeling and expression. We propose a two-tiered design and evaluation model. We exemplify this model through studies of three different affective interfaces: the Agneta & Frida system, the Influenc-ing Machine, and SenToy and FantasyA.