[[WMG: There is no Oni marriage proposal custom, Lum made it all up.]]
When Mako tells Lum about her plan to con Jariten into dating her by telling him that refusing would be a capital offense under Japanese law, Lum calls her "a true kindred spirit". (Lum telling her relatives and alien friends that the proposal thing was an ''Earth'' custom could account for Rei showing up later, and would explain why Mister Invader always seems so perplexed whenever he sees Lum and Ataru carrying on--he thinks it was ''Ataru'' who insisted on the "marriage".)
* Wasn't it more of an "If you grab an Oni's horns you get a wish." kind of deal? And when Ataru screamed about how he could finally get married while holding Lum's horns, she took it the wrong way?
** This troper remembers it was more like than a "Spoils of war" scenario. While Lum's father originally intended to invade Earth, in the end Eartheners and Oni boiled the conflict down to a contest between two single champions. Then Ataru won, loudly bragging about being finally able to get married. While the reader knows Ataru was speaking about Shinobu, Lum and her family had no way to know that bit of information. As far as they were concerned, the invasion failed and the Chosen Champion of Earth, after proving his superiority to the Oni Race, asked their princess in marriage. Basically Onis, as the losing part, owed Ataru, and since he asked Lum in marriage, they thought that understandable and desiderabile. By the time Lum found out Ataru was nothing like a hero and a champion, she had already fallen in love deeply with him.
*** Lum already knew he was nothing like a hero and a champion, at least in the manga: in that version, Ataru got her bra by accident halfway during the contest, and when she showed up at his home to get it back she discovered he was ''wearing it'', before Ataru's defence of the bra got her to flash the neighbourhood. My money is on her going with the chance because she needed an excuse to break up with Rei and Ataru was ''still'' better than him, and fell for him later.

[[WMG: ''[[Manga/FistOfTheNorthStar Shin, Juria and Jagi]]'' are students at Tomobiki, and ''[[Manga/FistOfTheNorthStar Raoh and Toki]]'' are former students]]
Kenshiro ''has'' appeared as a Tomobiki High student (in the same class as Ataru!), after all, and we know that Shin and Juria are Kenshiro's childhood friends... Only, we never saw them because they're in different classes (maybe even the same). Also, Jagi is another Tomobiki High student a year above them and Raoh and Toki are former students because Ryuken lives in the area, and enrolling his adopted son at the same school was easier than enrolling them at different schools.
* It would explain the lack of delinquents at Tomobiki: with Kenshiro, Shin and even Jagi around defending the meek, who would ''dare'' to be a bully?

[[WMG:Ryunosuke's mother is no better than her husband and Ryunosuke should not miss her.]]
The manga clearly states that Ryunosuke's mother abandoned her husband. We can guess ''many'' reasons to NOT want to remain with Fujinami, but why she would leave her daughter behind? Either she thought that Ryunosuke would be better off with her father for some reason... or she did not care leave her daughter with that loony.
* It’s possible especially if she has any half decent memory of her mom as a little kid to miss her in the present (especially with her father). Heck if she lived with her mom she might be treated better, also no arranged marriage and being able to dress like a girl are things she wants, things her mom might give her (no effort on the moms part).

[[WMG:Urusei Yatsura story happens after ''[[Anime/MazingerZ the]]'' ''[[Anime/GreatMazinger wars]]'' ''[[Anime/UFORoboGrendizer in]]'' the ''Mazinger'' universe.]]
There not only are giant robots, cyborgs, aliens and spaceships in this universe, but also several characters (Ataru in a Sakura's dream; Azusa...) use the RocketPunch or a variant, quoting ''[[Anime/MazingerZ Kouji Kabuto]]'' verbatim. So that the ''mazinwars'' happened several years before the show -and humanity learnt how building mecha during the conflict-. And that was because the Oni invaders chose challenging humanity to playing tag instead of invading Earth directly: they had seen what had happened to the ''[[Anime/UFORoboGrendizer Vegan Alliance]]'' and not wished sharing their same fate.
* That explains as well why nobody is -too- fazed with all the craziness surrounding them.
[[WMG: Ataru Moroboshi is afraid of commitment]]
This explains ALOT of things with his relationship with Lum, hell he even states in the second movie that he loves Lum but because of her he can't chase women anymore.
* That isn't so much a "wild mass guess" as an "obvious recognition of his defining character trait."

[[WMG: Ataru knows he is in a cartoon]]
At some point, Ataru realizes he is in a cartoon. That explains how his character evolves from being an ordinary everyman, to a mad trickster who constantly takes advantage of the fact that nothing can harm him, because he knows he'll always come back unharmed in the next frame. That also explains how he is able to materialize out of nowhere whenever someone mentions a girl or goes on a date. He knows there are no rules and he loves it.
* Cherry may also be aware.

[[WMG: Shinobu caused Ataru's fear of commitment and CasanovaWannabe ways]]
Early on, and especially at the start, he wasn't ''that'' lecherous (and indeed, in the first chapter/episode he ''barely cared about Lum's beauty''). Then she became jealous of Lum and got back on her promise of marrying him, and he started showing interest in other girls. Coincidence?

[[WMG: Everyone at Tomobiki High has figured out Ran is an alien, they just don't care]]
On day 1, she stole Kosuke's youth with a kiss in front of pretty much the entire school, and Lum was trying to warn Ataru against her. It's pretty obvious she's an alien, and the fact she knew Rei even before he visited the school would have confirmed it... But since her weird side doesn't appear unless she's dealing with Lum, why should they tell her they know the thing she's clearly trying to keep secret?

[[WMG: Ataru is incredibly good in the bed, and just making out with him can leave a girl addicted]]
Why would Shinobu put up with Ataru's lechery for so long, or quickly convince himself he was cheating on her with Lum when he clearly didn't want anything to do with her at the time? Because Ataru is that good at pleasing a girl and Shinobu couldn't leave him until Lum kept them separated long enough, and with Lum growing possessive so quickly Shinobu thought they were making out.
* As a corollary, that's why Shinobu can't find a boyfriend after breaking up with Ataru and she's so short tempered: she may be beautiful, nice, and a good cook, but every time she kisses a potential boyfriend she expects the pleasure Ataru would have given her, and the fact the lecher all but ruined her for any other man is just that annoying.
* As another corollary, Ataru could totally get a harem if the other girls actually let him kiss them (and if one of them was Oyuki or Ryoko there would be no money problem)... But his attitude means they'll ''never'' give him a chance.

[[WMG: The Principal served in World War 2.]]
The series takes place in the early to mid-'80s, and the Principal looks to be in about his early 60s, which may mean he was old enough to get drafted. PTSD might explain [[CloudCuckooLander his personality]].

[[WMG: How can we work ''Series/StrangerThings'' into UY WMG's?]]
The series is (as of 2023) experiencing a boom in popularity in the West thanks to the anime reboot, and TheEighties is ''still'' one of the more popular decades for nostalgia, which ''Stranger Things'' obviously builds heavily on. Considering both series feature supernatural beings meddling with humanity, it's not too much of a stretch.

[[WMG: Ataru ''does'' eventually get a harem... After marrying Lum]]
Ataru is canonically the man with the highest libido in the entire universe... And if after the marriage Lum discovers she can't handle it, she'll get her friends involved. First her best friend Benten, then Oyuki who's already shown her interest, then Ran butts in to mess with Lum and can't leave anymore, and then Earth girls start getting dragged in. Starting with Ryoko because not only Ataru knows he'll need the money (Oyuki may be rich, but better not take any chances) but also to mess with Mendo.
----