Be it at the office, the gym or the school gate, we've all encountered women who live to make others miserable. Because sadly, that nastiness we thought we said goodbye to at our high school, follows us like a bad smell through our adult life.
Jordan Baker investigates the different types of mean women, and how to deal with them - one at a time.
When Sally* took up martial arts, she joined what she thought was a well-run gym owned by a friendly young couple, John and Vanessa.
She was welcomed into the fold; her fellow students were friendly, and Vanessa seemed keen to make her feel at home.
Sally loved her new training centre. She threw herself into the work and social activity, and after a while, a friendship with one of the instructors, James, became romantic.
Their flirtation blossomed into a courtship that would one day become an engagement. But when they revealed their relationship to the others, things changed for Sally. She discovered that James' ex-girlfriend was friends with Vanessa.
From that point, Vanessa became not only frosty, but nasty. She encouraged the other students to avoid Sally. She no longer invited Sally to social activities, but made sure she knew she was excluded. She became highly critical of every aspect of Sally's training — her technique, her fitness, her commitment.
Sally's partner, James, didn't take Vanessa's behaviour seriously. For him it was 'petty girl stuff', and both of them needed to grow up.
Sally found the whole experience hurtful and confusing. She could understand James' ex-girlfriend might be upset about him meeting someone else, but why was Vanessa so intent on revenge? Why were the other women joining Vanessa's vendetta? And why couldn't James see what was going on?
Sally blamed herself. Maybe she had done something to offend? Perhaps there was something wrong with her?
"I would often cry before I went to training," she says. "I kept going because it was the best way I had found to cope with my grief. I thought I'd left that kind of behaviour behind in high school — turns out I was wrong."
Like Sally, many of us experienced that particularly female kind of warfare at high school, when hormones, insecurities and playground politics created a breeding ground for nastiness.
There was silent treatment, exclusion, backstabbing. There were girls who made nasty comments, or spread false rumours, or giggled about others, and who seemed intent on belittling, humiliating and undermining.
Unfortunately, some of those 'mean girls' turn into mean women. They take their behaviour into adulthood and continue to inflict it upon other women in their friendship circle, their family or their workplace.
During her years as a psychologist, Meredith Fuller estimates she has seen thousands of women coming to see her about their struggle to cope with a campaign of subtle nastiness from the "bitch" (her terminology) in their life.
According to Meredith, bitchy behaviour is not as overt as bullying — it's too nebulous to pin down as deliberate sabotage.
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"The difference between bullying and a bitch is you're talking about someone who is engaged in behaviours that are very subtle," says Meredith, the author of Working With Mean Girls, a women's guide to handling bitchy behaviour.
She defines it as sustained pattern of behaviour that amounts to an emotional campaign, but one that is so faint that most women think it's their problem — that they are too sensitive, or reading the behaviour wrongly, or inadvertently triggering the problem.
"It creates a bit of a time bomb," says Meredith. "You are still not sure if it's really happening, or if you're imagining it. As time goes on, you start to feel lower in confidence, your immune system is affected, and you are doing things that really compromise your career."
Of course, men are no angels, and can be both bullies and bitches. But often, says Meredith, conflict between men is overt — they argue at a meeting, then laugh about it over lunch.
Women can be more devious, perhaps because they were never encouraged to be assertive as girls and so learned different ways to meet their needs.
"Some [of these behaviours] are unconscious," says Meredith. "They don't realise what they are doing, and they probably don't want to hurt another person, they just have inadequate relationship skills and they haven't had a good interpersonal model — they are doing the best they know with a limited range of resources.
"But some women think it's funny. Some say they love to put the boot in, to see what other people are made of, and they see that as, 'If you can't stand the heat in the kitchen, get out'."
Women who experienced schoolyard nastiness can feel, in adulthood, like they are having a flashback.
"The healthy part of you is re-triggered for a good reason, it's like your body is saying watch out, this person is not safe," says Maureen. "If you have had that experience in early life, sometimes you can start to worry — 'Is it me, do I attract it?' You really start doing the self-blame. Then you feel ashamed.
"There are a lot of women who have idyllic childhoods, and they never noticed what went on. They haven't got any war wounds whatsoever, so when these odd sort of behaviours start happening, and they are more shocked."
Trying to engage a male partner on this issue can leave women feeling even more isolated, says Meredith, because many men struggle to understand how hurtful and confusing the experience can be.
"Their male partner says, 'I don't know what the problem is, just tell her to get lost', and the husband thinks he's solved your problem," she says.
"One woman I spoke to, who is very senior, said she would come home, and she would start crying in front of her husband and sons. They would think, 'What's the matter with you?'"
Not all 'bitchiness' is as nasty as Vanessa's campaign against Sally. It's the co-worker who deliberately embarrasses you in a meeting, the friend who puts you down in front of others, or the critical mother-in-law.
One teacher went to see Meredith about another, more senior teacher at school, who was constantly sniping at her choice of dress, saying it was inappropriate for a boys' school.
"She would continually scold me about what I was wearing, to the point where I would get nervous walking past her," she says.
"I could wear a neck-to-knee robe, and she would find something wrong with it. I began to worry about going to work, it completely undermined my confidence."
Another woman described a boss who treated her female staff like children. She did this loudly, and in front of lots of people.
When she was a few minutes late to a conference and slipped in at the back with a male colleague, her boss demanded — in front of the entire gathering — that she sit down the front, "where I can keep an eye on you". The male was not required to do the same thing.
From the cases Meredith studied, she developed rough categories of 'mean girls'.
The Excluder: She fails to acknowledge you, appears not to hear your hello, and might giggle or roll her eyes while you're talking.
The Insecure: She loves telling people what to do, and will tell you what you already know. She doubts other people's competence.
The Toxic: She is overly friendly at first, and attempts to engage your sympathy with tales of how horrible other women have been to her, but becomes needy and demanding.
The Narcissist: She needs to believe that she is the most popular or admired person in the office, but puts down others and gets irritable if things do not go her way.
The Screamer: She screams or yells, using intimidation to get the job done. She is perceived as being in a perpetual bad mood.
The Liar : She can be charming, but is unreliable and always finds excuses for her behaviour. She lacks empathy and puts her needs first.
The Incompetent: She is not up to whatever job she has, but goes to great lengths to hide it, including passing off other people's work or ideas as her own.
The Not-a-Bitch: She disagrees with you, reminds you to complete tasks you are required to do, reinforces office protocols and holds you accountable.
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Meredith's tips for protecting ourselves from this behaviour include never engaging in gossip with them, keeping our distance and changing our expectations.
She also encourages women to take a long hard look at themselves and ask — 'is it possible I've got it wrong?'
Meredith also says, women need to ask themselves whether the problem may actually lie with them. Am I being stand-offish? A bit over-sensitive? Am I really doing my job as well as I can, or is there room for improvement? If a friend or co-worker is being touchy, they might have a good reason.
"We're all not perfect, and sometimes when we're stressed, we can revert to a ratty way of behaving," says Meredith. "Women are trying to juggle too much, we are very busy, and there's not a lot of time to reflect.
"Sometimes we do things we don't intend to do, but no-one ever tells us, so you just keep doing it and you don't realise the impact you can have on someone else."
Meredith counselled Irene, who worked in retail, and was a nervous wreck thanks to a deeply conscientious manager who wore her diligence as a badge of honour, and berated others for failing to live up to her standard.
"It just made her really difficult to work with, because you were always on tenterhooks, and always felt like you were failing, no matter how hard you tried."
The counselling helped Irene understand the manager's behaviour. "I would deal with those things very differently now. She had targets to meet and had a boss on her case, and she was extremely stressed all the time," she said. "She needed a scapegoat."
Sometimes it takes an outsider — a counsellor, perhaps — to help us work out whether we are victims of emotional campaigns, or just upset by someone's manner or tone.
But we can also help ourselves by trying to de-stress and look at the big picture, says Meredith. When we have breathing space, we reflect on how significant this person is in the context of our whole life, and whether we can do anything to better manage our own responses.
The difference between encountering mean girls at high school and mean women in adulthood is that back then, we were young and insecure; as adults, we have experience, perspective, and choice.
Sally, for example, left Vanessa's martial arts training centre and found a new one, where she was valued and respected.
And one day, when she confessed why she had left her earlier centre, she found a little vindication too. Other women had left for the same reason.
So she wasn't imagining Vanessa's behaviour, and it wasn't her fault; it was just that, mentally at least, some girls never quite leave the playground.
*Names changed for legal reasons.