The human capacity for grief. It just isn't capable of providing an adequate emotional response once the dead exceed a few dozen in number. And it doesn't just level off - it just gives up, resets itself to zero.
Alastair ReynoldsNightside, cities glistened in chains, and a spray of tinkertoy habitats girdled the planet. Gossamer starbridges reached from the equator towards orbit.
Alastair Reynolds