"Men often hate each other because they fear each other; they fear each other because they don't know each other; they don't know each other because they cannot communicate; they cannot communicate because they are separated."
-- Martin Luther King, Jr.
As the old saying goes, can't we all just get along?
Since Humans Are the Real Monsters
, this means that they all hate each others' guts, and that's one of the things to make a signature Crapsack World
. Here are common tropes regarding characters who do not get along at all, or at least have some issues with each other.
A super-index to Civil Unrest Tropes
. Compare Hatred Tropes