Carol was my complete nemesis. At the time, I began work as a sales & catering assistant/executive secretary at a large hotel. Carol had occupied the position before me, but was promoted to Sales Director right before I was hired.
From Day One she made my life there living hell. As I had come from the medical field and had no prior experience in this type of work, there was a learning curve to which I had to adjust. Carol didn't understand that, and literally jumped on every mistake I made. She was good friends with the General Manager, our direct supervisor, and would trip over herself to get to her quickly and inform her of all the trouble and mistakes I had made. She never failed to point out how *she* did something, or to remind me of all of my shortcomings.
The hotel chain (which is worldwide) established an employee reward program whereby customers and guests of the hotel and restaurant would nominate an employee they had felt went above and beyond the call of duty for them. The reward was a green ribbon you got to proudly display beneath your name badge. After receiving a couple from some clients I had worked with, Carol went to the GM and complaining, saying that I shouldn't be eligible for rewards of this type since I could technically be considered 'management'.

Once, I casually mentioned to her that I was planning a vacation in August of that year, and wanted to see if our hotel chain had any rooms available then at my destination. I couldn't figure out then why she scoffed and turned away from me. Another employee later told me that she was angry because SHE wanted to take a vacation in August too, and was afraid I would beat her to the punch. After checking hotel availability, I put in for my vacation that afternoon with my boss. On her desk, I see Carol's vacation request, which hadn't been there before my conversation with her. That turned out well though, since Carol's vacation request was the week before mine, and that meant I didn't have to see the witch for two whole weeks (of pure bliss).
Carol smoked like a chimney in the office (this was back in the 80's, before the banning of smoking in the workplace), but when another manager who was profoundly allergic to smoke complained, she blamed me and exonerated herself completely, saying she only smoked in her car when she was out on sales calls.
Carol would also throw work assignments for me into the out tray on her desk even if I was standing right next to her. So it was routine for me to be at her desk, emptying the tray. Once, I did this just as she was returning to the office and was accused of spying on her and snooping through her things. Later, I discovered she had good reason to worry about someone snooping: she had been documenting, in
painstaking detail, every single error I had made since Day One of my employment with the company.
Shortly thereafter, Carol went out on medical leave for several months, during which I took her place as Acting Director of Sales. I even acquired a couple new accounts for the hotel during that time, one of which was in an office park just down the road from our hotel. Why Carol never thought to approach them was beyond me, but that certainly rubbed her the wrong way since it made her look bad to the GM. When she returned from medical leave, she put up a huge "Welcome Back, Carol" banner and had coffee and donuts brought in to celebrate her return. Apparently that wasn't enough for her. She huffed back into the office and barely spoke a word to anyone. Later that day, the GM revealed that Carol was angry that no one had kept in contact with her while she was on medical leave, other than the couple of times the GM had called her for an update on her medical progress or for some paperwork issue.
Just a mere month after that, Carol was fired for non-performance. She'd spent so much time trying to railroad me that she neglected to go out and drum up new business for the hotel! I'd never been so happy or relieved as that day in my entire life.