When jelaous people are nasty..... why do they do it and does it really solve anything?

Congratulations, you answered your own question. Hurting people, hurt people. This girl was clearly hurt in her early childhood, and it caused her to become a bully and narcissistic. Not everyone raised by bad parents becomes narcissistic, but a large percentage do. They put you down because someone in their early childhood hurt them and made them feel small, so in their mind they put others down in order to feel bigger. If they are pointing out your flaws, no one is noticing theirs. They like to pit people against each other, and stir things up and create chaos, so no one will notice their short comings. Narcissistic people don't have to come from bad families, but most do. Narcissistic personality disorder is 85% alcoholics and/or drug addicts, 15% they believe are children who were raised by alcoholics or drug addicts, or just simply put down by someone when they were small children. Someone hurt them when they were little and made them feel small, and that is why they do it to other people. They have to put others down in order to make themselves feel bigger. (Not that that is an excuse.) They think they are God like, Saints, with grand egos, I call them destroyers, they just destroy people. In their mind they are right and the world is all wrong, they don't have a problem, you do. They put others down because they are bullies, and cowards. They put others down because they have no self esteem. If they are putting you down, and pointing out your flaws, no one is noticing their flaws. In their mind they think it is their job to put others down, it is their duty. They are social, and the rest of the world is anti social, they are perfect and you are the one who is flawed. They cannot and do not take responsibility for their actions and behaviors, so they will never say they are sorry, because in their mind they have done no wrong, they have done nothing to be sorry for. They can go to therapy for years and have no change in their behavior or actions, because in their mind they are saints, and perfect, so they have nothing to change about themselves. I am not really sure if they even comprehend how they hurt other people. The best thing to do is to stay away from these people if possible. They cannot change and they will just bring you down. My in laws are this way, so I know how you feel. After 20 years of abuse they are now banned from my house. While they had the benefit of putting us down and hurting our feelings, they did pay a price. They are now retired and none of their children, their spouses, even their grand children, none of us want to be around them. They enjoyed abusing us all those years, and now they spend their holidays alone. They do pay a price. I am sorry she said mean things about you.