The ubiquity of internet-capable mobile devices enables individuals to use online communication and social networking sites (SNSs) almost anytime and anywhere, which may foster addictive usage patterns. SNSs provide manifold options and suggestions for social contacts and experiences, which can increase social comparison processes that potentially cause negative affective states, such as envy, dissatisfaction, or fear of missing out (FoMO). This empirical study (N ¼ 226) investigates associations between the tendencies to maximize outcomes and to procrastinate and problematic social networks use. We assume socially driven cognitions such as FoMO and the tendency to switch or cancel appointments at short notice, named “social zapping,” to mediate these effects. We tested the hypothesized effects through structural equation modeling. The results confirm positive associations between the mentioned constructs. Procrastination fully mediated the effect of maximization on problematic social networks use. Furthermore, FoMO mediated the effects of both maximization and procrastination. The findings indicate that tendencies to maximize and to procrastinate lead to problematic SNS use, especially in cases where specific fears and intentions to find/to not miss a potentially “better” alternative for social experiences are high. Potential relationships and reinforcement mechanisms in the developmental process of problematic social networks use are discussed.