Although they are not relevant to the main plot, some of the stories of people at Katorga in the aftermath of the singularity's explosion, discovered through notes, audiologs and time echoes, are really tragic. Examples: the audio of a little girl, member of a group of survivors under constant assault by mutants, has the recorder as her only toy left and her father tries to make her stay silent because they would be heard by mutants; you can clearly hear the poor man is in tears. A series of time echoes show three men escaping; cornered, one of them decides to shoot his companions, then he points the gun toward himself... but he's run out of bullets. He spared them the suffering but couldn't himself.
Let's put it this way, a "Gamzee Made Me Cry" thread showed up on anoncomm after this post. A brief description: Like many of the station's residents during that event, he came in contact with black rock and died horribly. Unlike most of the station's residents, he died with a calm and heartbreaking dignity.
Rattmann tends to generate these.
Karkat's breakdowns over not being able to protect his friends. He flips from silly (smashing piles of GPSes because they were "serving the robots" or ranting off a parody of Time Cube) to heartbreaking so easily.
I SAW US DEAD
I SAW US DEAD SO MANY GODDAMN TIMES AND IT JUST KEEPS HAPPENING AND WE'RE ALREADY DEAD THERE'S NO FUCKING CHANCE BUT I'M TRYING TO WARN YOU IDIOTS AND I CAN'T LET HER FUCK US OVER AGAIN.