Go read The Ones Who Walk Away from Omelas.
tl;dr There's a utopian society with literally no strife. No rulers or politicians, police, or soldiers. Everyone is happy and they're free to explore whatever intellectual or creative passion they desire.
When each citizen reaches a certain age, they're shown the city's secret: In a small, dark closet in a cellar, with no windows, there's a child sitting naked and dirty. The child's malnourished, and mentally ill. It gets fed every now and then by being kicked awake and given a bowl of greasy corn meal, and it lives in its own filth and excrement.
Everyone of age knows about the child, and most accept it. If the child were to leave the room or otherwise be treated well, all the prosperity of Omelas would end forever and the city would be destroyed. Eventually, some people choose to leave the city, and never return.
-Would you walk away?
-Is it more cruel to accept the child's sacrifice, or to abandon the city?
-Is it justifiable to rescue the child and destroy the city?