AIBU to feel frustrated over being copied.

Give us some ideas of what it could be

I understand how frustrating this is for you op. I’ve recently realised that a very good friend has decided to copy my style, down to the shade of nail varnish I wear and it has made me feel a bit spooked. We have the same build and the same name, these can’t be changed but she is wearing clothes and shoes that she feels uncomfortable in because they look good on me. We are in our 60s!

Absolutely, but you couldn’t do anything about it if someone else decided to dress like Annie Hall at work!

It doesn’t really matter what the individual items are it’s how you put them together. I like menswear… I like shirts, blazers and sometimes a tie. I have short hair and wear a certain type of glasses. None of it is unique in of itself but in my large workplace I was the only woman who dressed in that style. If another woman came along and started dressing like that after a period I would feel a bit miffed. ( and if that person was my sister 🤷‍♀️)

Anything you can buy that easily isn’t exactly niche. Not regular in this country but regular elsewhere I have a strong suspicion of what it is.

OP, you can do absolutely nothing to control other people’s behaviour, only your own. If you’ve asked her to stop copying your clothes and she’s denied doing it, you’re back with what you can do yourself. If you feel like an idiot with your sister at the same workplace dressed the same, I would, as pps have suggested, evolve a new work uniform without the hobby clothes aesthetic, and only wear them outside of work. Or you continue to dress as you usually do and deal with feeling like a bit of a clown.

was she like this when you were growing up? Is she younger than you?

This is very common in neuro divergent Pele and I noticed this in my AuDhd daughter when she was a child. To be clear all of my kids are nd /adhd/audhd and 3 of the 4 wear literally anything, their personality OSS not defined by clothing and it’s not seeing they could be bullied over as they just didn’t/ don’t care . Very individual styles and string sense of self. Not my oldest daughter had to have the same as everybody else when she was younger to “fit in”. Add she got older and hot her teen years where we tend to find our own sense of style, her style very much depended on the group she was on the periphery of ( but never fully part of). At the time autism and adhd in girls wasn’t really a thing and I called it camouflaging or magpies to get psychiatric team. It comes from very a deep sense of insecurity and a desperation to mimic somebody that presents as 100% comfortable and confident in their own skin. Think of Jack black. He’s not particularly attractive or handsome or stylish, but his absolute confidence, musical talent and arrogance means that millions of women across the world would love to spend time with him.

Wicca?

Adult Disney - gotta be

What the what are super chick vibes? Are you dressed like a giant chicken?

Well I’d say it’s born out of insecurity. Were you always the high achieving sibling ? My friend is massively insecure and will “farm” taste from everyone around her. Shes not copying my look head to toe anymore but would have done in the past. She still checks out a new purchase, which sounds like a normal friend behaviour but it’s in an anxious way - as if not having it she is falling behind. This leads to some compulsive shopping behaviour and debt which is a great shame. I’d love her to feel content with who she is as a person. If your sister is younger than you maybe she feels you were always more accomplished and successful.

Roller derby? Just wear very plain stuff to work, no need to wear your hobby stuff there anyway.

Ooh a secret hobby! I don't really understand why you look fine wearing it alone but if there's two of you you look like wallies?

Why did she start working where you work? Was she already starting to copy you then, because this has vibes of stalking behaviour.

My sister is obsessed with me, and not in a good way. She went through a copying phase as well. Now she basically hates me.

Do you actually have or want a relationship with her?

Yeah I've got to be honest, while not as odd as her copying you- tbh even her coming to work at the same company would have annoyed me as well - having a hobby that is so all consuming it influences how you dress and act every day comes across as a bit weird too.

I can't even work out what would come under that category - my initial thought was "horses" but that's hardly niche and tbh if you were going around in full jodpur and hunting jacket at work that is also odd. Then thought about something like steampunk but that hasn't been around that long...either way, whatever it is, there's a line between dressing with a token nod to your interests (fan merch related t shirt, black dress if goth, white blouse and braided hair if cottage core/historical renactment etc) while still being professional, (particularly as it sounds like you're in a fairly senior position) which, even if she did still copy you people wouldn't really make the connection (2 women wearing a black dress, wow!), vs what sounds like doing full on cosplay every day.

You can still dress more full on outside of work, and restrict how often you see her.

Do the two of you still have your parents? Does she have a partner? I'd talk to them and see if they've noticed anything, if it's as drastic a change in her appearance and the way she behaves as you've suggested, they probably find it a bit weird too.

Tbh you could even bring it to HR - not coming at it from a "copying my clothes" angle but a "I've noticed a complete change in the way she behaves and she won't talk to me about it, I'm wondering if her manager has noticed anything or has any concerns about her MH?" They have a welfare responsibility towards her too, they might not be able to tell you the outcome of any conversation but her manager sitting down and asking her "we are concerned you're suddenly dressing in Japanese lolita fashion" might be enough to shock her out of it a bit?

I think you both sound odd, you because you've let this particular interest become your whole personality and your sister because she's copying you.
Maybe you both need to branch out a bit?