Why do people avoid sitting next to strangers on buses?
An empty seat is sometimes a negotiation, not an invitation.
People usually avoid sitting next to strangers when other seats are available. The decision is rarely personal. Instead, passengers silently preserve options and personal space for as long as possible.
At first glance this looks selfish. Yet the behavior often reduces social uncertainty. Sitting next to someone requires a small negotiation about space, movement, bags, and eye contact. The hidden mechanism is Silent Spatial Agreements. These unwritten rules help strangers coexist without speaking.
The interesting part is what happens next. Once a bus becomes crowded, the same people who protected space moments earlier quickly adapt. Social expectations change and sitting beside strangers becomes normal rather than uncomfortable.
People think buses move passengers between places. Sometimes they also move strangers between different social rules.
