Individuals in a group, who repeatedly experience that their group's policy selection system does not decide in their favor, may feel unheard and increasingly develop system disbelief. System disbelief (i.e. discontent with the performance of the group's policy selection system) may be detrimental to the performance and the welfare of groups in several ways. It may dramatically reduce the psychological well-being of group members, leading to a substantial decrease of their willingness to provide work effort, financial contributions, or cooperative coordination. In extreme cases, system disbelief may lead to anti-social behavior (e.g. arbitrary destruction) and foster the willingness to engage in subversion (e.g. sabotage) or insurgence (e.g. coordinated rebellion). Studying the individual characteristics and the environmental parameters that give rise to system disbelief in a laboratory experiment, our study contributes to understanding the dynamics of discontent with group decision processes and the ensuing destructive behaviors. Thus, our study may provide insights valuable for the design of group decision processes that are welfare enhancing by increasing the resilience towards system disbelief.