[adult swim] had no problem with what was put in the show until they asked why the creators killed Sanser.
The ending to "Combaticus" was a bit sad, too. Sure, he lives on in some sense as the "new god of war", but he had to die in order to save his genetic donors from being crushed to death. And his "parents" seem to mourn awkwardly, believing that his only weakness was his compassion.
And with considering how "The Trouble with Triples" shows that the Twins were bullied and mocked by their elder brothers since youth, and that their father usually neglects them for being "failures" with the exceptions of when he wants to bring them home and does this time, to their upset, it seems that Combaticus was the only being that may have actually unconditionally CARED for them. And yet they consider compassion to have been a weakness, even though if Combaticus hadn't had it, they wouldn't have survived. But for another interpretation on the part, it seems that had Combaticus not seen Specimen 7 saving the Superjail staff, it possibly wouldn't have occurred to him to save his own "parents" as well, and he may have simply remained as narcissistic and cocky as them.
Jackknife's past can be considered quite tragic, especially the flashback of his father selling his toys for booze after Jacknife sees a bunch of kids playing with toys in a sandbox and cries over the childhood that was robbed of him and (possibly) led to him being a criminal.
The death of the world famous racer in "Superjail Grand Prix".
The ending of Time Police I, which doubles as this and Nightmare Fuel-worthy, where the woman holding a baby is gunned down, and the baby, still in her arms, is crying.
How much Alice wants to be a mommy (despite that a sex-change operation doesn't grant the patient the ability to make or carry a child). She may be big, buff, tough, and badass, but she has been show to be EXTREMELY nurturing towards children. In addition, commentary for "The Budding of the Warbuxx" states that one of her secret desires is indeed to be a mother (which is likely why she latched on the idea of being a godmother for the Twins' baby... and that didn't go so well).
Some also find the revelation of Alice having been fired from her previous job for being transgender to just be as sad and unfortunate for her character. If not the act itself, the fact that Alice had feelings for her old warden and assumed she could actually earn his love adds to the sad part, as it turned out he was a gay man and fired her on the spot once he saw "Big Al" was now a woman. That, and she walked in on him with his actual lover.
The episode "Superfail" is quite saddening. The episode seems like the usual wacky Superjail fare, filled with the usual dark comedy and a plot loosely parodying Weekend at Bernie's when Jared accidentally knocks the Warden out cold. But spliced into this episode are more tidbits into the Warden's past. We see him as a child once more, as he tries to show a guard dog love by giving it a cookie. This angers his father, the Prison Mogul, and while the child Warden is feeding the cookie to the dog, he shocks his own son by turning on the electricity to the fence. As if that weren't bad enough, he then forces the little Warden to KILL the dog with an ax, stating that "A guard dog is useless once it's known love". The kicker? It was a puppy.
Jailbot's apparent Heroic Sacrifice at the end of "Burn Stoolie Burn" gave fans a bit of sorrow. Even with the show's tendency to snap back, the sight of Jailbot burning in the flames made for an ominous scene. To add to that, Jared tries to escape the jail, but is pushed back into the fire by Lord Stingray and left to burn as well. The cliffhanger then shows that Jared had programmed his escape pod to go to Ultraprison, presumably so he could meet his girlfriend again. Instead, Lord Stingray and Alice are headed on an unwilling trip there.
Though clearly played for laughs, there are viewers that find the idea that Ash could never have a normal life of happiness to be sad, what with his out of control fire powers that destroy everything around him when he gets too excited. He even tries to think back to a "happy" moment in his life, but said happy moment quickly ends in disaster and the deaths of others around him. The Warden's own flashback to never being able to experience a pony, while not as openly grim as the "Superfail" example, also tends to be cited as sad and disturbing (considering his father had them turned to glue before his very eyes).
Jailbot breaking down in 'Jailbot 2.0' is rather sad, but what seals the deal is The Warden's reaction by crying by Jailbot's side is quite painful to see considering his personality.