This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Grim Tales from Down Below
Irwin's death, Hoss and Raven's Senseless Sacrifice, and Him taking Mimi away from Blossom. Seriously, it just keeps getting worse.
Every single thing to do with Mimi. Break the Cutie doesn't even begin to describe what her life's being like. She's the daughter of freakin' HIM and Blossom, and though there are still questions about why Blossom would even have sex with Him, there's no doubt that it wasn't something she would do voluntarily. Then one of her friends/protectors betrays her surrogate family and it results in her home being completely destroyed and her friends being killed. Then her dad shows up to take her away. Then her last few friends pull a Taking You with Me in a futile effort to destroy Him once and for all. Then she's forcibly taken from her mother, has her hands cut off, an evil symbiote corrupts her soul and she shuts down emotionally AND verbally in order to cope with the literal torture she goes through every single day in order to still be the kind of daughter Him wants her to be. Her only friend and nanny is then killed when she defies Him, she is forced to break into the Grim Reaper's castle to steal something. Only she was sent there to be 'taught a lesson' about being disobedient. And that lesson? Being forced to relive the single worst day of her life: the day her home was nuked, her friends killed and being taken away from her mother forever. And if Junior hadn't intervened, she would have then had to face Mandy's wrath. And to top it all off? She was the one who killed her own mother!
And if you thought Mimi's life before HIM came to take her away was good, the latest comic reveals that she spent most of her time hooked up to a machine that enhances her precognition abilities, acting as a preliminary global warning system whenever a super-powered being was about to commit an evil act. Worse, the machine left her physically drained to the point that she needed a wheelchair, impaired her mentally so that she lost her speech and weakened her spiritually. And since she was so fragile when she wasn't hooked up to the Nephilim, she was never allowed to leave the facility she was kept in, even likened to a 'pet in a gilded cage.'
It's pretty painful watching Minnie's descent from a soul so pure that despite her demonic parentage she was afforded a place in Heaven to the envious, cold-hearted monster her mother wants her to be. Is reconciliation between Junior and herself too much to hope for? Signs point to yes.
Mimi's flashback to her birthday before she was taken away from her her mother. She 'asks' Raven to get her a chakra gem for her next birthday, and Raven tries to talk her out of it, that a chakra gem isn't just a shiny jewel, that it helps her to control/suppress the darker aspects of her powers and soul (i.e, the parts of her that come from her demon father)....as soon as she said this, most people would realize the real reason why Mimi would want one. Cue her next birthday, the last thing Raven does before she sacrifices herself is to ask Jeff to give Mimi her present.
Jeff's sad expression when he realizes that Mimi does remember her last happy birthday...
Chi has a vision that is highly implied to be Blossom's last memory before she was killed. From Blossom's point of view, we see Mimi standing over her - crying and her eyes glowing white - and bloody knives float in the air, about to strike and the shadow of Him in the background. Blossom reaches her bloodied hand towards her daughter, calls Mimi's name one last time...