Narcissistic Personalities & Sociopaths
Conscience is a type of judgment, that tells us what is right and wrong. It begins in early childhood, when (hopefully) parents teach a child what he can or cannot do (beginning with "no!"), then gradually how to tell right from wrong. Conscience-building continues in Sunday School, regular school and within the family and the neighborhood. We learn what's right and wrong on a personal level, a spiritual level, and a social level -- if we wrong our friends, they leave us.
When this process doesn't happen correctly (dysfunctional families, not enough supervision, etc) a self-motivated conscience never completely develops. This is what happens with most lawbreakers, narcissistic personalities, and sociopaths. Jason Blair (the New York TImes journalist who made up facts and interviews) didn't have a well-developed conscience, and neither did the soldiers at Guantanamo Bay prison. If they weren't properly supervised, were allowed to regulate themselves, or given orders that were wrong, they couldn't make conscientious choices.
Abusive men are narcissistic. They have "Jekyll and Hyde" personalities, which means that they can be very charming when they're not being abusive. Women who stay in abusive situations focus on this charm, and deny the abuse. They also have experience of their husbands smoothly talking their way out of any responsibility for misbehavior, for example if she once called 911 and he got the police to believe nothing was wrong. The woman feels hopeless and helpless, that no one will believe her or help her get out. She's also ashamed, and doesn't want people to know her misery.
Various women have combinations of all or some of these reasons for staying. Women who do this are focusing all their energy on what the man thinks about them, and their low self-esteem and insecurities are feeding the obsession. It's not only obsessive, it's narcissistic. It's like trying to look at yourself through his eyes. What a woman is supposed to be doing at this stage is figuring out what she thinks of the man. What he thinks of her is up to him, and out of her control. She needs to be observing him, considering his actions and what they reveal about his character.
Trying to alter your own traits through guessing what he will like and not like will not lead to a real relationship. You're not giving him a chance to get to know you as you are, and worse yet, you're not getting to know him.
A friend can also be narcissistic -- this means she was emotionally arrested at about two years old, and hasn't matured (emotionally) much beyond that age -- she's just in a grownup body. She's not exactly codependent. She turns on the charm when she wants something from you, but doesn't recognize your existence when you want something from her.
She's not doing it on purpose, it's all she's capable of doing. That's why it's not going to change, and that's why you can't talk her into being more reasonable. It's hard to resist those charming ways, but you'll never find a mutual, reciprocal relationship there -- it will always be all give on your part, and all take on hers (except when she's charming -- which won't mean what you think it means.)