TL;DR: I don't even know.
I am livid.
I have an employee I'll call CK. She's 6 years older than I am. She's a great worker, very intelligent, works hard, puts in her hours and her productivity is great. The quality of her work is close to 100%. As a worker, I could not be happier with her.
As a colleague she can be great. She's got a sharp sense of humour, is a good conversationalist usually, and has a background to much of the history we work with in our research.
As a person, I think she might be a little out of touch.
This started some time ago. There was someone in our office with whom she just didn't mesh; it went both ways between those two and I figured, hey, some people just don't gel. No big deal. They didn't fight or anything, they mostly just ignored each other. Some time later, I'd start getting text messages from her during work hours (not unusual) about how "no one" in the office liked her (save me; also, unusual). I reassured her that that was definitely not the case. She eventually confided to having few friends, and since I enjoyed her company overall - I should mention our office is a social group, we chat during the day and will go out together for dinner/drinks - I suggested we grab coffee or drinks sometime, that she didn't have to feel lonely/rejected by the office. I even invited her over for dinner on one occasion. After she was busy every offer I made (4 total), I stopped asking, thinking maybe I was putting pressure on her. One day, after a date, she sent me an angry text about how I had specifically not told her about the date (but told everyone else in the office) to make her 'play the fool'. The day before I had literally been discussing with her what restaurant we were going to; she said that she didn't realise I had been talking about a date - and therefore it was my fault.
Yeah, the office teased me for four days, but it was secret... Well, anyway.
Some time elapses and I get a text from CK about how two other colleagues and I had shared "a look" about CK, a look that apparently she 'recognised' to mean, and I quote, 'what a raving c*nt'. I wasn't aware there was a 'look' for this, but hey. Learn something every day, I guess.
Anyway, now that I had been listed as part of the group that didn't like her, I wasn't sure what to do. I let her cool off for a few days and later reassured her that we liked her company, etc. This was all before I had been promoted, so I was on equal footing with her in terms of our jobs; she had at one point said she'd leave when I was promoted because of how I was acting - I don't know what I was doing, despite having asked; many times her answers are things like "Well, it's obvious." Useful. She eventually seemed to warm back up to talking, but definitely less frequently. I was content to let it lie there; if she wanted to come out of her shell more, it was clearly going to be on her terms, not mine. I was still happy to go for drinks, etc if she liked.
After I got promoted, she gave a long rant about various people in the office: G "is weird and talks a lot" (NB: a recurring complaint from her is that the office is too quiet, so wtf), F doesn't like her, D -who she had never worked with, but only met for like 20 mins one time- was going to make this job 'suck even more'.
And then... today. Today I had to move J from the computer next to CK to a different computer because J had trouble logging in. CK, noticing J move, but evidently not paying attention to preceding conversation, tells me that it's 'obvious' - as it always is to her - that J moved because she doesn't like her. And I'm just internally screaming and pulling out my hair in frustration; outwardly I'm calmly explaining that the computer was having issues and tech support will fix it tomorrow. I had specifically put J there because I knew CK liked her - or, thought so! - even though it would have been way more convenient for me to put D there. I tried to a nice thing by kowtowing to her attitude.
The thing that makes me so upset isn't even the effort I went to to make the seating more palatable to her. That's fine. I don't mind, really. What, an extra 30-60 minutes of setup for J? She can handle it and she won't mind.
The thing that makes me feel so ... hurt, frustrated... She accuses people of disliking her, over and over, and yet she's the one who has lists of reasons, both real and imagined, to dislike everyone else.
ARGH ARGH ARGH