This paper presents two models that exemplify psychological factors as a determinant and as a consequence of social network characteristics. There is an endogeneity considered in network formation: while the social experiences have impacts on people, their current psychological states and traits affect network evolution. The first model is an agent-based model over Bianconi-Barabasi networks, used to explain the relation between network size, extroversion, and age of individuals. The second model deals with the emergence of urban tribes as a consequence of a smaller propensity to communicate with different with different traits and opinions.