Part of the appeal of Superman as a concept is the tension between wanting to save people from suffering and knowing that he can't just solve all the world's problems. Sooner or later, though, he's just gonna say 'screw this' and fly millions of lightyears away. For good.
"God's End" is another fan comic by writer Gerado Preciado and artist Daniel Bayliss, the guys who did that incredibly dark Batman/Joker story back in November. This one's shorter but has an equally raw view of a superhero's relationship with other entities.