A lot of reviewers of Kanon complained that the scene in which a character gets hit by a runaway car looks unrealistic, since the victim cannot be seen anymore. In reality that is likely to happen when the car actually covers the victim or when the victim gets catapulted out of sight, as can be seen on footage of real accidents. And, after that episode was aired, people found footage of an accident on YouTube which was identical to that scene. It's quite possible that it was the one used by the animation team as a reference.
The Eldritch Abomination portrayal of Angels in the series is actually more accurate to what the Bible described them as (mind-bendingly bizarre and strange) than the humans with white wings we see in most religious art.
A number of commentators, including this reviewer, have noted a lapse of realism in Tokyo Magnitude 8.0 - a conspicuous absence of rioting and panic in the wake of the disaster. Ironically, the 2011 Sendai earthquake revealed that this was in fact a perfect representation of Japanese cultural sensibilities. The reaction of the Japanese people was indeed extraordinarily level-headed.
It should be noted that many western media reported the more or less total lack of looting in Kobe, following the Great Hanshin earthquake of 1995, with considerable undertones of awe. Add to this that the Japanese are widely considered as a society striving for consensus and collective good and this turns into a major case of the reviewer not doing his research.
Not to mention, lying on the Pacific "Ring of Fire", they're kinda used to these things...
It was a different case with the Kanto Earthquake in the early 1900s where riots did go out of control.
Yasuna from Kashimashi: Girl Meets Girl has a physical condition where she can't see men's faces. It comes off as a blur in the anime, and an outline in the manga. A lot of fans and critics believe it to be an outlandish made-up disease or a psychological problem. Her condition is actually very similar to a real disorder called Prosopagnosia, albeit hers is probably a mild form... In the manga at least. One sufferer of the disorder has stated that the portrayal is rather realistic.
The anime version makes clear that it is a psychological problem, though, considering what happens by the end. The climax of the anime and manga are very different.
Used in a very 'meta' manner in Asobi ni Iku yo!. Eris - a bona-fide Cat Girl alien - gets targeted by a Secret Society of hardcore sci-fi fans who simply refuse to accept that humanity's First Contact is with a Human Alien - they want something PROPERLY alien! Even better, Kio brings Eris along to help his movie-club shoot a sci-fi movie, but not only is Eris not alien enough, her Assistaroids look fake, and - here's the kicker - her spaceship, which she can remote-control, uses a form of superstring braking to maintain flight at very slow speeds, which resembles... strings, going upwards from the corners of the ship. So her ship ends up looking ridiculously fake in all their shots as well. Ultimately, they decide to scrap the sci-fi plot and shoot a Romantic Comedy instead.
When people want to paint the Leo from Gundam Wing as a shoddy piece of junk, they tend to cite scenes in which merely being near the blast from Wing's rifle is enough to destroy one. This is, however, a rare aversion of Convection Schmonvection in the Gundam metaseries, as a gigantic wave of super-charged plasma would generate some pretty intense heat.
The same effect is shown in Gundam Unicorn, in which a mobile suit is blown up when a discharge from the Beam Magnum passes near it. The other pilots take this as an indication of the beam's extreme power.
Not involving any sci-fi elements, in Mobile Suit Gundam SEED Destiny, Shinn keeps around his dead sister's cell phone and listens to her voicemail message when hes down. Now, people do keep answering machines and old family movies with people that have died. With the Fan Dumb however, they view Shinn as a sick fuck because of this.
Some viewers of Sora No Woto complained about how ludicrous the old house perched on a cliff shown in the first episode was. The whole series location is an accurate recreation of the Spanish town of Cuenca, and the house is a popular tourist spot.
Pokémon's May, Dawn, and to a certain extent Misty (even though the last one is actually flat-chested, something explicitly stated on the show) are often accused of being unrealistically "well-developed" for a 10-year-old. In reality, puberty for young girls has gotten much lower in recent generations because girls are fatter than they used to be (a girl needs a certain amount of body fat before she can begin puberty). Thus the average age for puberty to start in girls is actually at nine and ten years old. Not surprisingly, this shocks people in real life as well.
Lest we not forget, the world's youngest recorded mother was five years old well before such chemical exposures were likely to have happened; individual differences in this regard are, and have always been, huge. And in any case, minor breast growth can happen even before the puberty kicks in with full force.
It's also not uncommon for precocious puberty to be a temporary thing, environmentally or otherwise, such as in an Italian school in the 1970s where boys and girls started growing breasts — believed to be from exposure to contaminated beef or poultry. The effects disappeared within 8 months.
Plus, babies have been known to grow breast buds and secrete "witch's milk", i.e. infant lactation, due to exposure of estrogen and other hormones from their mother's womb or breast milk.
On a completely different tangent is Brock's ethnicity. Most Americans think that he is Latino or Black or so on. Turns out that it's really not that uncommon for Asian people to get that dark.
This, despite that a minor celebrity in the U.S. is Julie Chen◊, a former newsanchor, host of Big Brother and a talk-show host in the off-season.
There is a legitimate complaint that characters can survive truly horrendous injuries without dying, although the oft-ignored in-universe explanation is that how much vitality a character has affects their survivability (it's just that the reader doesn't get to see the Life Meter). However, one of the examples often used for how ridiculous this gets is Hiyori being cut clean in half and, instead of instantly dying, surviving long enough to receive the medical attention required to save her life. Humans in real life really can survive after having been cut in half if they receive the required medical attention soon enough after the accident has occurred. The major difference is that magic was able to reattach the severed halves so hiyori could fully recover whereas this is a bit beyond real life medical science. However, the complaint is that she stayed alive to receive medical attention at all, and that issue is possible in real life.
There is a complaint among some American fans that it's unrealistic for fifteen year olds to be living alone without any legal guardians and without state intervention even if Japanese culture dictates such issues are an extremely private matter. However, in Western countries, including America, teenagers who are legally minors can indeed be found living alone without any guardians or state intervention. This has been shown in psychology research to be for any number of reasons, ranging from parental abandonment/neglectnote Indicated to be the case with Mizuiro who has a mother but clearly isn't being raised by her. He's good at seducing older women to play a parental substitute role in her stead, death of any/all guardiansnote This is Sado's situation whose parents died when he was eight and whose grandfather died sometime later, parental abusenote Orihime's parents were so abusive, her older brother kidnapped her and ran away from home when he was 18 and she was 3. He raised her himself before dying when she was 12. She's lived alone ever since, walking out on the parentsnote When Uryuu realised his father hates being a quincy, he lost all respect for him and walked out on him. It's strongly implied that his father's secretly keeping a protective eye on Uryuu and in fact quit being a quincy to protect Uryuu from something, or arrangements with family that allows for the child to be independent of all direct intervention except for financial supportnote Orihime's independence is actually funded by an aunt who has nothing to do with Orihime on a daily basis but who funds her on the understanding that she does well in school. Orihime does very well in school. In short, all the examples that crop up in the manga do in fact happen in real life even in Western countries.
Hourou Musuko fans bemoan that Takatsuki no longer considers themselves transsexual by the end. People cry that it's unrealistic and OOC but studies have shown that most children who can be considered transgender grow up to be cisgender identified when they're older. Also it's left ambiguous in the end whether they're really cis or it's a phase due to confusion, having no support, and lack of confidence.