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.
In Spain, especially in Catalonia, they LOVE Shin-chan in the same way Americans love The Simpsons (maybe more), to the point where the author went there several times and befriended the official translator - who eventually appeared in the manga. Hell, it can be argued that it's more popular there than in freaking Japan itself! There was even a Japanese TV show that made a special episode to explain it. Meanwhile, no matter how many dubs, (Gag-like or otherwise) are made, it seems the series will never catch on in America.
In the anime, there was a story about the Noharas vacationing in Barcelona. Even though there were lots of quite outdated and slightly off stereotypes (a tour guide named Carmen, paella, toreros, south-american looking people and flamenco), they included some nods at the catalonian fans (such as Shin-chan saying the paella is "Molt bo" (Very good) or doing the "Ass Dance" saying "culet, culet" (What Shin-chan says in the catalan dub, roughly "booty, booty").
The phenomenon isn't as widespread in Portugal, but there you can't be an anime fanatic without at least recognizing Shin-chan.
The series is also popular enough in Korea (they, instead, call Shin-chan as "Jangoo") to even had the movies dubbed and a line of snacks sold in stores.
In Indonesia it is widely recognized alongside Doraemon and Dragon Ball. The original and the new manga series can be found in any Indonesian bookstore and the anime is still running on TV. It would be a massive accomplishment if there is not a Doraemon or a Shin-chan volume selling in any place that sells manga...
Ho Yay: Shin-chan teases Kazama (Georgie) a little too much. Heck, Kazama is also too much tsundere around him, so when something happens, it's mostly played for laughs.
Squick: Are the closeups of Shin-Chan's and the Kappa's genitalia really necessary?
In the Gag Dub, The Flamer having to leave the school, and Penny suffering from a broken heart because of it.
The original manga has some touching stuff that the anime has to tone down for comedy's sake. Miss Ume's relationship with Doctor Tokuro, to mention something... when he dies due to a terrorists' attack in his hotel when he was in South America. You have Miss Ume, who was unlucky with men, finding a stable relationship with Tokuro, that was transformed in a long-distance relationship not so much before his death. She even fell into depression with suicidal thoughts because of his fate. The anime leaves it at least in a bittersweet note before he was Put on a Bus.
The Scrappy: Misae/Mitzy gets this for being abusivetendencies. Sure, Shin is no boy scout, but she reacts to everything he does with the maturity of a 12-year-old.
Ai, who manages to combine Royal Brat, Abhorrent Admirer(to Shin) and Karma Houdini(nobody ever calls her out on her condescending behaviour) into one annoying character when she's seen. She's also this in-universe, nobody actually seems to like her, save for poor Masao, who has a crush on her but is often treated like the dirt under her fingernails whenever they interact.
If Ai is included, so does Penny. After she Took a Level in Jerkass, she develops a Hair-Trigger Temper and became bullying towards the gang (particularly Masao),mostly forcing them into playing "Extremely Real Tea Party" with her in a normal day. She's also this in-universe, where even Shin Chan sometimes scared of her.
Uncanny Valley: Mitzi's face can take on quite a bizarre appearance when she gets angry, especially if there's an Art Shift to the less refined style, resulting in her face looking VERY thin and skull-like.
What an Idiot: Shin Chan + Lighter + Gas Leak = Home blown to Kingdom Come.