Has anyone ever had bad or negative friends, who just keep coming back?

About five years ago I messed up a friendship probably by being too much of a downer, and clingy. Since then I did a lot of work and a lot changed.

I could see why she didn't want to be friends anymore, but what I found unacceptable is that she would treat me like **** in front of other people. When I would go to social events and parties, even though we had lived together for about 3 or 4 months, and had been really close, it basically seemed like more of a case of "you don't fit in with my circle." I remember being absolutely shocked and humiliated by she and her friends refusing to even acknowledge my presence, and practically force me out of social events with rude comments, etc. So much so that I was unable to attend parties and other events with her present because it was so horrible and awkward. People actually came up to me later and told me that they feltl sorry for me.

During this time when I was going through a hard time, other people stood by me and are still friends with me to this day. At the time I was unemployed and not in a good place.

To try to make a longer story short, a few years later she shows up again, wanting to be my big friend all over again. Mainly because I think I was trying to forgive her, I let her back into my life and re accepted her on facebook. I regret it. She pretty much did the same thing again, and, to make matters worse, in the year and a half absence from me she had managed to alienate a whole lot of people, piss them off, and the people who outcast me, were now outcasting her, so she basiclally came back to me. When would I learn my lesson.

Every so often I hear from her, when something goes wrong of course, like when she was fired from her job, she contacts me. Or, she will invite me to a b-day party, I don't want to come, I say I'm busy. Every time this happens, her brother offers to pay. A few years ago they invited me on a vacation, insisted, and he paid. I don't like people to pay for me for a lot of reasons. I don't want to owe anyone. When I was not able to come to the b-day, they upped the ante by offering to pay.

So the summer comes around again. Have not talked to her in TWO YEARS. She is always forgetting my number, losing it, etc., and I get a message again to call her brother. Why after two years? I lived with her five years ago, maybe six. What is the connection anymore?? Is he going to offer to pay for something else, for a relationship I don't want? The few times we hung out she always reminds me of how I stayed with her a couple of months when I was out of work, five years ago. She doesn't even know me anymore. And whenever she introduces me to her friends, somehow the circle of people she knows all manage to shun me. What a coincidence...what is she telling them?

And why are they contacting me out of the blue? Something must be wrong.