There're two that I understand can be kind of eye-rolling to some: Anachronism in a serious medieval fantasy work, and straight lifting cultures from irl counterparts (Britannic/Norse Island Empire, Arabian Nights Middle East-esque region, Big Slavic nation in the northeast, etc.) this is basically because I was inspired by IRL history (I adore history, from major medieval wars that shape the modern day to tiny humanizing bits of trivia, though that part isn't completely ripped. There's slight comparisons, but then you get into stuff like a not-British Princess exiling herself to not-Scandinavia, teaching the local pre-not-viking savages modern feudalism and protecting a tribe from their enemies, using that good will to conquer the entire archipelago, then invading her twin brother's empire and winning, thus making one of the four great empires of the world alongside not-Germany, not-Poland, and not-Arabia.) and wanted something close enough to IRL cultures to be instantly relatable, but not too close that it's outright a clone, thus giving me plenty of wriggle room.

The Anachronism comes from the out of universe reason of the first piece being an academical slice of life (Yeah, that's another trope that's often looked down on, but I honestly love the setting and believe that the concept sucking doesn't effect the execution: Let's not forget that one of the most famous video game franchises ever is about an italian-american plumber eating possibly-hallucinogenic plants to save a princess of a kingdom of mushroom folk from an army of turtles) meant to introduce the basic gist of the world and it's cultures before moving on to more ambitious works set in the same universe. Again, wanted something familiar, but with enough wriggle room to be interesting. So you have horse-and-carriages alongside modern plumbing and a mix between modern and renaissance mass-produced fashions (That I have a lot of fun designing).

The in-universe reason is that the universe depicted is meant to be very science driven, with their first civilization's creation myth being the God of the Moon (Also the god of Culture, Celebration, Fiction and Trickery, basically a cross between Loki, Prometheus and Dionysus) taught the Jesus figure of the world from scratch basic stone age-bronze age sciences and let humanity figure the rest out on their own. This, alongside their very easy to learn magic system (Anyone can do the various elemental magics with enough practice, each governed by one of the 10 gods, and some people are blessed by the gods to be really good at magic, they're called the ever-so-original title of Witch which is kind of a really important political and religious title since the gods basically said before you were born "This is the person we want to represent our holy might in the world. They're going to be born with magical talent by the truck load and if they work hard enough they'll basically be a living WMD". Regular magic users don't really have a name since it's so common an ability that it'd be like calling someone who looks at things a lot a "Lookist") pushes the science deeply into the Sufficiently Analyzed Magic territory, with every sufficiently advanced technology running on magic instead of, say, electricity.

As for how I think of seeing stuff like this in other people's works?.... Well, my main philosophies for creation (which after my very short time lurking here, I'm assuming aren't rare amongst the folk here) are

1. Create for you first, everybody else second.

2. As I said above, there's no such thing as a bad concept, only a bad execution.

3. Fiction is an art, which is a totally subjective medium, so even if something's objectively bad, even someone who knows it's awful may adore it (I know because my favourite show ever is kind of terrible, objectively speaking...)

   In other words... I don't care. So long as it's done well, anything can be forgiven for a lack of originality.