Finn reassuring Susan in her first appearance that "grass can't hurt you". Come later seasons, and grass does hurt Susan and Finn. A lot.
Every scene of Lemongrab abusing others became this after news got out in January 2023 that his VA, Justin Roiland, had been arrested on charges of domestic battery against and false imprisonment of his then girlfriend.
After "Holly Jolly Secrets," anything the Ice King has ever done that was meant to be funny could be called this, as all of his antics are the product of a deteriorating mental state.
In "The Chamber of Frozen Blades," Ice King tells Dr. Princess that he's a widower, the joke being that he actually didn't know what that word meant. Come the reveal in "Holly Jolly Secrets," and as far as anyone knew at the time, Ice King/Simon had a fiancée before he went mad.
The scene of PB pushing Lemongrab onto the floor and making him cry becomes cringe-worthy when it's revealed later on that Lemongrab thinks of PB as his mom.
Marceline standing outside in the snow, staring into the window in "Holly Jolly Secrets II" is a punch in the heart now that it's revealed that Marceline was once a daughter figure to the Ice King, and had to watch him lose his mind.
At the end of Too Young, Lemongrab leaves on his camel, looking miserable and sulky, muttering to himself as he returns to his home. Then we find out later that he has no friends, or anybody, back home.
Jake joking in "Jake the Dad" that his kids are grown up. But in "Puhoy," when BMO reminds him of this, we see him struggling not to cry.
So Marceline's dad just ate her fries. Doesn't seem like it's bad enough to refuse to talk to him ever again, right? But in "Memory of a Memory" we see the fries he was eating were in a broken-down abandoned diner after the apocalypse. Chances are food of any kind was scarce and teenage nonvampire Marceline probably needed them more than her deathless father...
Related to the above: In the Fionna and Cake episode, Cake wore the Ice Queen's tiara and Fionna knocked it off Cake's head, yelling, "No! You might catch her crazy!" As "Holly Jolly Secrets" revealed, the Ice King's crown caused him to go crazy. And the whole episode is a Fan Fic by the Ice King... so he knows to a certain extent that he is not the person he used to be. Similarly, at the end of "The Eyes," Ice King, after spending the entire episode spying on Finn and Jake to learn the secret to happiness, ends the episode with the line "I'm...still not happy". Sad enough in context, but after all the revelations concerning his past, it starts to seem like he is subconsciously aware of what he's lost, on some level, and cannot be happy because of it.
"Too Young," viewed as the creators of the show intended, is an episode that goes from funny to heartwarming to rather dark. However, when viewed from the failed experiment Lemongrab's point of view, it's depressing.
An upset Lemongrab left at the end of "Too Young," and came back a year later. He mentions that his castle has no citizens. According to Word of God, the only people in his castle are his servants, and he has no friends. When Lemongrab goes home in "Too Young," he's returning to a life of near-total isolation.
Even though Lemongrab is really unlikable in it, "Too Old" makes it painful to rewatch "You Made Me!" After the events of "You Made Me!," Lemongrab becomes a happy, adjusted person who has a wonderful friend, and a creator who worries about him and cares about his feelings. Watching "Too Old" after watching "You Made Me!" is going right back to square one, back to Lemongrab's angry, isolated, self-loathing, sad, friendless, lonely life- and Princess Bubblegum reprimanding him and bullying him when he ends up royally sucking at his job.
In general, a lot of Lemongrab's scenes (especially his eventual treatment of Lemongrab 2 and his subjects) are hard to watch since in early 2023, Justin Roiland was fired from numerousshows due to various allegations made against him, ranging from unprofessional work behavior to sexual harassment.
Ash selling Hambo to that witch. It was revealed in "I Remember You" that Simon Petrikov gave child Marceline Hambo when she was scared and alone in the post-apocalyptic wreckage. Just when you thought you couldn't think of Ash as more of a dick.
While Marceline's journal song is already pretty harsh, given that she's admitting to being lonely, hating being immortal and pushing people away so that she won't get hurt, but there's one line in particular that becomes unbelievably heartbreaking after watching "I Remember You":
Marceline:(singing) They don't know what it's like to live forever and forget who they even are...
Similarly to the above, Marceline's line about not having friends was a Tear Jerker to begin with, and then it's revealed that she grew up in an irradiated, post-apocalyptic wasteland. She probably didn't have friends because she and Simon were the only survivors around.
In "All Your Fault," it is revealed that Lemongrab has suicidal thoughts. Remember the scene in "Too Young" where he walked out of a window? Or the scene in "You Made Me" when he purposefully fell out of one? Yeah.
All of the scenes of Lemongrab and his brother loving each other are really cringe-worthy to watch now that Lemongrab has partially eaten his clone, and is now abusing him verbally.
Cloris Leachman's character being reduced to a skeleton and later consumed by the molten lava is now now tragic in recent following Leachman's passing in 2021 from both a stroke and COVID-19.
