In this article, I aimed to examine the thresholds of reactivity at different levels by observing how social actors establish various action boundaries at both the individual and group levels. Drawing on social action theory developed by Weber (1968) and threshold models of collective behavior developed by Granovetter (1978), I analyzed the interplay of people’s habitus, environmental factors, and temporal conditions that shape their responses to perceptual injustices. Beginning with ethnographic observations of daily life on the Marmaray railway between Istanbul and Izmit, the research synthesizes gender-based interventions, inter-ethnic conflicts, class-based pogroms, morally motivated riots, and religiously motivated fanaticism within the framework of historical and contemporary cases. I considered norms, cultural codes, laws, and power hierarchies as factors that influence individuals’ acceptable and unacceptable behavior, concluding that reactivity thresholds depend on the balance between social recognition, legitimacy, risks, and potential rewards. At this point, I realized that tolerance or perceptual differences can transform into collective actions, shaping the spread or suppression of social reactions of approval or disapproval. Thus, the study offers new perspectives on behavioral patterns that govern participation, resistance, and the evolution of normative behavior in different social groups, while witnessing how individuals navigate between passive and active behaviors.