Insecure no talent they don’t want to help anyone but themselves

I think a lot of women's behaviour is innate, we are programmed to want to be the smartest and prettiest so we get the best mate, and pass on genes to create the best kids. Unfortunately it usually translates to being awful to other women in an attempt to make them seem worse rather than making ourselves better. We live in a society that values men over women so we are at a disadvantage, we are judged harshly by men and women, while excusing men for their actions.
The funny thing is if we just worked together we could make the world a better place. We could breed out lazy violent men, and have such easier lives where we are equal, we get paid equally, and men contributing equally at home.
But instead we worry about being thin enough, and having nicer clothes than the next woman. But we sit back, let men make decisions that affect our lives, because we would rather have the boys like us rather than work together.

yet on your own post you judge the woman involved with the married man rather than the married man? I don't agree with cheating full stop but it always seemed to be blamed on the woman.

Jealousy?

We have to see and meet everyone where their at and the choices they choose.
Everyone is doing the best they can with where they are at.
Including if nasty hateful words can come out of your mouth, even if you feel justified than you yourself need reflection (more so some of the other comments)
But even in your own post there is hypocrisy.

More often than not they are like that because it’s a defence mechanism. We all have them and use them however everyone’s is different.
In the same way someone might react different and become a different way after a certain event to another who might cope better, it’s not to say that the first way couldn’t have happened to you.

If it’s not your sort of people and you don’t have the strength of character or you don’t feel the need to be around them you simply move on. If it’s someone who your forced into the circle of then it’s up to you to be strong enough of character to not let it effect you and your own behaviour.

Hurt people hurt people

I don't really think there's all good people and all bad people. There's a little bit of bad in good people and there's a little bit of good in bad people. Honestly sometimes it's just what day you catch them on.

Because they’ve been hurt by other women usually

Hate young ones that think they look good with surgery and call you old when you’re 40 and think people at 60 shouldn’t drive and anyone over 70 should be in nursing home and over 80 should be dead

Because we are the weaker sex

People can be all different measures of evil.

But OP remember for every nasty bitch there are three nice ones.

Just don't let people get you down.
Just pity them for being so low.

2 main reasons (imo):
1. People are cunts (someone else pointed this out already)
2. Because we are often conditioned to compete with each other from a young age. It's sad, but true.

To make them selves feel better.

Insecure nasty dysfunctional - take your pick. I’ve recently cut off a relative who is exactly like this - she thrives on bringing people down, it makes her feel like she’s winning.

Cause some women are c*nts. Plain and simple