Uh. for a moment there I thought for sure you were working with my former coworkers. Actually, several of them are retired now and the company eventually went out of business. Most of them worked for the company a long time and would act like they were such good friends with each other, but if one of them was out of the office the others would gossip about that person. One of the women talked openly about her mental health issues.

What people like that are doing are trying to pit coworkers against each other. They are very manipulative people who get a sense of excitement from creating dissonance in the workplace. At my job, I was a major target for those bullies. There were a few people I related to well, but in front of the other coworkers they would ridicule me. I don't think they were necessarily trying to be cruel to me (they did it in a joking manner) but were trying to get in the good graces of the bullies to avoid being targeted themselves.

I did try to get along with everyone, but I was surprised once when a fairly new manager noted in an employee review that I got along with everyone in the office. Since it was obvious that several coworkers didn't like me, I had felt certain it would reflect badly on me. There were other times when managers came to me in private to inform me I was getting a raise and cautioned me not to tell coworkers because not everyone was getting a raise. So, managers will notice your good attitude and it will reflect in your job performance. Someone else's bad attitude toward you will not reflect badly on you.

There was also a woman from a church I went to who was friends with me, but was very condescending toward me at times. I was struggling then with depression because of my physical health and my workplace situation at another job. The woman would criticize me when I confided to her about my work situation, or even my health problems, but would complain about petty differences she had with her own coworkers and her own aches and pains. I finally began avoiding her for the sake of my mental health, other than greeting her. I know it's harder to avoid people you work with, but I do think you're wise to avoid your coworker as much as possible, except when necessary for the job and just to say a cheery "hello" and wish her a nice day.