It is a characteristic of human action and ISD that individuals plan what they do and evaluate the consequences of their actions. Difficult life situations or long-term goals, however, typically require decision-making without complete certainty about the result and, as we know, beliefs in the face of uncertainty are often distorted. We try, make errors, and then (have to) learn how to adjust probed strategies (Popper, 1972). We pursue life plans and strive for personal ideals that may become an important part of our self-definition. Nonetheless, identity or self-definition consists of several self-defining elements we have not intentionally planned. Of course, they could have been unintentional by-products of our expectations and wishes. Many of them have developed as products of chance encounters (Bandura, 1982) that were beyond planned calculation but influenced our situation. The aim of Chapter 3 is to become acquainted with some of the manifold mental processes involved when individuals build and disengage from intentions, and thus contribute to their own development. In the following, I focus on the short-term perspective of ISD and draw attention to the fleetingness of the moment, non-intentional processes, and affect.