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.
YMMV: Grave of the Fireflies
Accidental Aesop: Most people who see the film take an anti-war message away from it. According to the director, that wasn’t what he was going for at all.
Alternative Character Interpretation: A mass scale example, as the screenplay author/director wanted the viewers to think that Seita was being an overly proud little boy for not simply apologizing to his Aunt and asking to move back in. The majority of the audience, needless to say, saw him as one of the biggest victims in cinematic history — partially due to the lack of Jerk Ass moments compared to his Aunt.
Furthermore, it looks like aside from pride, there was the very pragmatic issue that his aunt was struggling to take care of them, and with the newly decreased rations they would have imposed on everyone beyond their abilities.
Angst? What Angst?: It is rather incredible how much time Seita spends with a smile on his face. However, it’s mainly for Setsuko’s sake and it’s quite fake. The best example is when he starts doing gymnastics on a bar to try to distract Setsuko from the fact their mother just died. It doesn’t work.
Glurge: Bennett the Sage and some others have accused the film of being this, essentially exploiting the tragedies of World War II in order to guilt 1980s youth into falling in line and being more like their parents’ generation.
Harsher in Hindsight: The ending is meant to be at least somewhat uplifting, as a clean, happy Seita and Setsuko look down on the modern, rebuilt city of Kobe. The only problem is, this is the Kobe that existed before the Hanshin-Awaji Earthquake of 1995. The movie itself is tragic, but if you happen to have lived in the area when the earthquake happened (or lost a relative/loved one, which was not uncommon considering the number of deaths), that’s an extra - albeit unintentional - punch to the gut... Even worse when you take Word of God into account and look at the movie as an ‘anti-rebellious youth’ film as opposed to an ‘anti-war film’.
It Was His Sled: The fact that the children end up starving to death is the most well known thing about this movie.
Misaimed Fandom: This movie has been lauded by many as an anti-war film, and has gained fans in anti-war movements due to its unflinching depictions of the cruelty and barbarity of war. Isao Takahata explicitly mentioned on several occasions that the movie is in no way, shape or form intended to be, nor should it be take as, an anti-war film.
Nightmare Fuel: Seeing your mother (or anyone close to you for that matter) horrifically burned and bandaged like a mummy.
Some Anvils Need to Be Dropped: As mentioned on the main page for this film, juvenile delinquency was at an all-time high from the mid ‘70s until the mid-90s. Takahata explicitly pegged the intended audience as Japanese teens whose parents had been of Seita and Setsuko’s generation. The intent was to say to them, ‘Look, you ungrateful little hellions, this is what your parents had to suffer so you could have your comfortable spoiled little lives.’
To give it a bit more context Japan at the time the movie was being made was experiencing a great economy. So Japanese children were living great lives and thus many grew a bit too comfortable and began striking out against there parents when blamed for being lazy much like the aunt did to Seita.
Squick: In the original novel, since Seita is deprived of all female contact and Setsuko has to mature really quickly, his and his sister’s relationship develops Brother-Sister Incest undertones. And remember, this was a semi-autobiographic novella.
Stoic Woobie: Seita, who is proud, courageous, and remains impassive in all but the most desparate moments.
Strawman Has a Point: The aunt, from a modern viewer’s perspective. Setsuko’s night terrors and loud crying disturbs the rest of the family’s sleep in a time when they need all the energy they can muster, and Seita doesn’t help around with fire extinguishing duty or earning a living when it’s very sorely needed, especially after the rations decrease.
Values Dissonance: Both a cultural and generational example. It was the director’s intention for the audience to see Seita as wrong from running away from home. Contemporary audiences tend to side with Seita and view his aunt's behavior as antagonistic and needlessly cruel: she repeatedly calls them ‘ungrateful little brats’ and ‘annoying’, sometimes to their face, even though their mother has just died. She also tries to pressure Seita into going to his distant relatives in Tokyo, even though he doesn’t even know their address. And when 12-year old Seita announces he is going away, taking his toddler sister with him, she simply reacts by saying, ‘Oh. Goodbye then!’ It's All About Me, indeed.
On Netflix, this movie was listed in the ‘Kids’ Anime’ genre. Fortunately, this is no longer the case, and the description on the website even says "[Seita and Setsuko] come to the somber conclusion that they can neither escape the hardships of war nor find enough food to survive."
‘Suggested 3 Up’ is on the back of the cover for at least one DVD edition. It also says ‘parental discretion advised,’ but that's rarely followed.
The original Central Park VHS contains the descriptor ‘suitable for most audiences’.
Averted in the case of the Australian DVD release, which is rated M: recommended for audiences 15 and up.