The current chapter addresses one of the most controversial concepts in psychology due to the challenge it poses to study from a methodological perspective: the mind. The chapter’s objective is to inform the reader that when accessing digital services, users come with preformed expectations shaped into mental or neural representations, a result of their previous experiences with the service or from what they have learned through social interactions with others. In the decision-making process, where users determine whether to use a digital service or others, they base their choice on a cognitive unit comprised of different mental representations that link a behavior to a reward. The behavior that is decided upon (which would include the use of the digital service) generates a set of expectations, which will be compared to the actual experience. The outcome of this expectation-reality comparison will elicit an emotional response that will become associated with the digital service, altering its value for the user. The congruence between expectation and reality is a fundamental requirement for a cognitively ergonomic design of digital services. Therefore, digital behavior designers must ensure that user expectations align with the reality of interacting with the digital tool. Designing user expectations should be one of the focal points in the design of digital behaviors, as a mismatch between expectation and reality can produce aversive emotions that may lead to the abandonment of the service.