Pronouns.
To be precise, trans and enby pronouns.
To be even more precise: trans and enby pronouns in Dutch.
Now, I'm well aware this is something that on all of this board I'm probably the only one who is ever confronted with it, since nobody else here regularly speaks Dutch (well, I haven't seen AmE or Wahad in ages).
Also, and I'll repeat this throughout...I'm not opposed or in any way against people choosing their own pronouns. I have no intent of coming off as sexist or discriminatory; I'm not sure I'll manage that, but please be aware that I'm trying. Anything coming off as insensitive or offensive, my apologies.
So, as far as pronouns go, T/NB people tend to fall into a number of groups.
First off are the ones who are still using "traditional" pronouns but maybe not the one expected. Born a woman, now identify as a man, prefer he/him. Sure. Presenting as male but preferring female pronouns, go right ahead. I might make an occasional mistake (if preferred pronouns don't correspond to presented gender) but I'll try. There's really no reason not to use the chosen pronouns here.
Secondly, there's the people who use their own, self chosen pronouns. If you really insist on people using....Xor and Zim (or whatever the fuck) for you....fair enough. It comes across (to me) as try hard edgy "I want to be dIfFeRent!" specialness, and to my mind in many cases a bit immature. OK, I can imagine that there are people who really are "out there" on the spectrum in a spot where they genuinely feel they don't belong anywhere on the he/they/she part of the spectrum and in such a case....sure. Most cases of people with this sort of pronouns I know, though, it comes off as more attention seeking than out of a genuine feeling of identity.
Now, I mean, I can accept your right to choose and the choice you made, even if I think it's silly or ridiculous, mind you, and I'll try - but I'll probably make mistakes more often than with the first group, not because I think the choice is any less valid but because it's harder to remember and especially to use properly. "I went to see Xandy yesterday, xor was really shaken up about the incident" or "I went to see Xandy yesterday, zim was really shaken up" both scan the same way to me so it's more confusing.
And while I'll personally try to keep using preferred pronouns even when a person isn't around, I can somewhat understand (though not agree) with people who revert to "standard" pronouns when referring to someone who's not present simply to avoid having to explain someone else's idiosyncrasies to a third party. Honestly, in this sort of case in a spot where I don't feel comfortable to use the preferred pronouns and explain, I'll usually just try to avoid pronouns altogether. Can be a bit clunky but not any more than using some unknown pronoun.
Third, of course, there's the currently most "visible" group - using singular they/them. I'm 100% aware that it's ancient usage of the words and I don't mind at all. For people who don't conform to either he or she, or those who don't know (yet) or whatever, it's probably my preference as it's easy and clear and in most cases not that clunky*. I've now met someone who insisted on using they but wanted singular verbs - so "they is going to the butcher". That feels weird to me as it scans wrong and moves it more towards the second group, but, again, their choice I'll try to accommodate. Throughout all the Age of Man, singular They has used plural verb conjugations, so I might mess up but no problems.
Now, the first and the second group, my reaction stays exactly the same in Dutch or French or German.
The third group, though...now, again, I'm willing to try and follow whatever the crap someone chooses about their own identity. I don't particularly care, and I try not to judge. My pet peeve is simply this: the... "default" pronouns for enbies in Dutch are Hen/die. Which translates roughly to Them/that. The Dutch word for "they" is the same as for "she" (though with a different verb form) so I can see why they wouldn't want to use that one....But "them" just ISNT the same type of pronoun. "I spoke to Xandy and them said them will come" is just grammatically wrong. And yes and no, I know, the "they're doing it wrong grammatically" is a go-to bullshit argument for people against the singular They in English, and I do mean it when I say people can choose and I'll try to follow preference. I'm not saying there's a great alternative, like I said, just using the "they" word would be akin to calling them all women which is obviously not the intent. While Dutch is a gendered language, I still do feel why these people don't want to use the translations of "it/their" (Het/hun). The Dutch "it" is neutral gendered, but that's "neither", not "both or other". There probably are some out there who use those, but I've never met these.
It's their choice, and I try to follow it, but it just sounds absolutely wrong every time. it's like someone choosing "there" as their possessive pronouns. Sure it's possible, it just looks incredibly annoying.
TL;DR: the Dutch version of "they/them" is "them/that", using a "wrong" type of pronoun, and it annoys my grammatically cold and distant heart.
*When the NB character on Star Trek Discovery first asked to use they/them it felt quite natural and normal. At the end of the episode the writers forced in a conversation between two characters about them that felt forced, but that was because it was badly written and 25x "they" and "them" felt shoehorned in, not because "they" in itself is cumbersome.