The Restaurant at the End of the Universe: Loner Hitchhikers (prompt 3)(chapter 26)

In chapter 26, Arthur and Ford find themselves stuck on a ship full of millions of useless members of society that is heading for a pre-programmed crash landing on a remote planet. While on the ship and after crashing, Ford and Arthur remain isolated. Instead of helping the crew unload the millions of frozen people from the ship, they start to look around. And, as soon as they can, they leave to try to find a way off the planet.

This suggests to me that Ford and Arthur see themselves as either better than or completely separate from these people. Since they aren't from the same planet, Ford and Arthur feel no obligation to help save the lives of millions of frozen people. (Eventually, the ship sinks into a swamp with millions still frozen on board.) Perhaps as a result of their travels, Ford and Arthur feel as if they belong to a class of their own. 

For Arthur, this is a little more understandable. His planet is destroyed and he still hasn't gotten used to the galactic new world he now lives in. He clearly feels isolated from and ignorant of his surroundings throughout the story, and it is very clearly showing itself here.