It confused the hell out of me. I was never sure where I stood.
I remember one time saying to my sister, she (my ex) is going to break up with me, she hates me. Then the next day it was fine.
Another time, the week before our break up, she hadn't been speaking to me for a week and we went out to dinner with my parents, pointed out some of my flaws at dinner to my parents, but then talked about the future and how they would have to visit more. Exactly one week later she ended it.
It's unsettling, I never knew what mood she would be in coming through the door. It made it impossible to plan anything like drinks out or dinner.
It confused the hell out of me and my mom, as well. One day, it was, "She just wants to be friends now." A few days later, it was, "Mom, she wants to live with me. She wants to be with me." My mom didn't like her to begin with, so the push/pull really pissed her off.
I also stopped planning things. I got tired of her canceling on me all the time, so I did things by myself or spent time with my parents. This caused her abandonment fears to show up, and I would try to make up for it, but then she would say that I was being clingy.