Marketers have devoted their efforts to comprehend the essence of negative electronic word-of-mouth (eWOM) since it was first introduced to understand brand crisis and the fact that social media facilitates rapid consumer communications that exacerbate the situation. This motivates marketers and researchers to investigate the complexities behind negative eWOM in order to contain potentially large-scale brand crisis. Our study proposes a novel mental state model based on existing theories of individual intrinsic motivation to engage in negative eWOM as derived from studies in the psychology of entertainment. Our model explains how individual perception of the brand may change from the initial exposure to negative contents to either feeling relieved or losing interest. We demonstrate the plausibility of our model by performing multi-way parameter sensitivity analyses with an agent-based simulation of the diffusion of brand crisis in a social network and measuring changes in the agents’ social perceptions over time.