In many cases, people are not “suddenly turning bad,” but are pushed along step by step by a series of psychological mechanisms: first, the disorder brought about by the broken windows effect, along with what the Lucifer effect and the Stanford prison experiment reveal about situational factors and power structures, quietly lowers the behavioral boundaries of individuals; then, in groups, the bystander effect and the diffusion of responsibility dilute individual accountability, making people more likely to go along with the crowd, while the imitation effect further amplifies this shift; at the same time, long-term suppression and frustration continually build up under the frustration–aggression theory, becoming an internal driving force for behavioral outbursts; and once a boundary is crossed, people rationalize their wrongdoing to find excuses for themselves, making their behavior “acceptable”; ultimately, under the High Threshold Effect, small transgressions keep escalating, gradually breaking through the baseline line people originally held.