There is an unwritten rule on the bus.
No one shall sit beside a stranger unless absolutely necessary.
It is a rule that everyone on the bus obeys without uttering a word to each other.
All strangers silently acting in unison.
The group shall only tolerate sitting beside another traveler if every seat with a buffer seat between it is taken.
If all seats are taken and two seats free up, then the nearest most awake person will automatically leave their seat to respect this rule and ensure two people sitting between four seats.
For the uninitiated, this is not something to take personally, as if the person sitting beside you is moving away because you smell.
It is simply because all members of the public are terrified of strangers and would prefer to sit alone.
Thomas Duggan 