These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Many of the characters have lost their entire families to the Zombie Apocalypse and subsequent collapse of society in Japan, though remarkably few of them seem to be feeling much stress over it. Perhaps justified in Shimauu's case, as it has been implied that she had been so traumatized by the ordeal that she's simply blocked it out of her mind.
If Chiyosuke is guilt-ridden about accidentally killing Floaty, he's sure good at hiding it.
While she was pretty broken up over her father's death in Season 2, Rachel seems remarkably laid back about being separated from her mother between Seasons 2.5 and 3.
Wallaby, who is one half of the physical representation of what humans refer to as 'God'... or something like that.
Though Vladimir does take his share of hits, his character was explicitly created to take other characters down a few pegs when the person writing him felt they were getting too powerful. Unfortunately this also means anyone facing him is screwed, because the most they can hope to achieve is a narrow escape. Victory is not an option.
Amber, sort of. She was originally intended to be rather plain-looking, but then other characters just kept finding her attractive...it probably helps that she's socially awkward and a massive science geek.
Misato once lamented the fact that both her sisters were far more attractive than her, and yet she was the only one of them who was ever able to get a boyfriend.
In the Discussion Threads, there are occasionally pictures of the entire cast as analyzed by certain cast members. This one,◊ done by resident Woobie Rei Kakizaki, has a horribly tearjerking one when she gets to Kagura's Mother's picture: "Are Mom and Dad and Ran and Misato angels now too?"
They Changed It, Now It Sucks: Some people's reaction when things shifted away from the first season's more or less random shenanigans over to a more plot-based format during the during the second season, and again during the third when the cast began to feature more and more side characters as opposed to just sticking to the core casts from Azumanga Daioh and Yotsuba&!, as well as incorporating more serious dramatic elements.
Toy Ship: Miura seems to be trying to induce this with Chiyosuke and Ena.
Trapped by Mountain Lions: Chiyo in Purgatory and Female Gang Member in the Undisclosed Location are just two of many examples.
The Woobie: Torako, Steven, Sakaki, Kagura, Rei, and Ran.