Jamal Faraji in his PhD thesis explores the role of user behavior in enhancing the effectiveness of energy communities within local energy and flexibility markets. Energy communities are essential to achieving climate neutrality in the European Union by promoting self-sufficiency and integrating distributed energy resources. Recognizing that individual member behavior significantly influences community outcomes, this thesis aims to develop a framework that incorporates both the heterogeneous preferences and bounded rationality of users in centralized energy sharing problems. By addressing how these behavioral factors impact energy communities' performance, the thesis also explores optimal user participation in energy and flexibility markets and examines strategies for the community actors to manage the effects of sub-optimal decision-making.