I have an arch-nemesis here in the office. A woman was hired about 5-6 years ago as a customer service rep and her personality is just to be a bully - to coworkers that she dislikes, to colleagues at insurance companies (claims adjustors, underwriters, etc.). It's how she gets results - she does things her way and verbally beats people up until they submit to how she thinks things should be. It's also her response to stress. When she's stressed out, she lashes out and says nasty things about people.
The trash talking got so bad that she would slam down her phone and talk shit about her clients openly after a conversation. She'd repeat the conversation to anyone around, summarizing how this person offended her and lay down some vulgarities for everyone to hear. She'd say the same things about people in our corporate office that we work with. It got so bad, and so annoying that I was talking to my wife on my phone one day and she heard this woman's voice through my telephone. If I was talking to a client and my coworker decided to spout off, my client would have heard the vulgarities - that can't be happening. She actually made passive-aggressive bullying threats aloud, directed at me and for me to hear, in response to me turning up a white-noise machine that I keep at my desk to drown out background noise in the office.
So I reported her to HR twice within two years for the same issues. The HR department had numerous complains about her from people in my office, people in the corporate office, and third parties (clients/insurance vendors) that had called the corporate office to complain about her. Nothing really changed after the first time. Her response wasn't to think about how she comes to work and behaves. I was out the day that HR talked to her and learned that after she was finished with the conversation, she went around the office to complain to anyone who would listen and point the finger at me, saying "HE got me in trouble."
The women in this sales team that she works for all believe that they are entitled to having privacy in the office. So in their minds, I'm being nosy by sitting at my desk and reporting things that I overhear. Uh, hello - this is an open office setting, with low cubicle walls. 20 people all sit clustered together. If you think you should have privacy, take it behind closed doors. If we all can hear things said in the open, nothing is private.
The second time, my boss told me that there were consequences and I believe that she was put on probation. Her boss made her move her desk away from mine, so I don't overhear as much. Her attitude hasn't improved at all, but at least she's not openly and loudly saying nasty things for all of us to hear. It's just amazing that there can be 10+ people that complain about someone, but they'll point the finger at the one person that they think is the instigator of their problems without thinking about the common denominator - their own behavior.