She stood up my best friend not once, not twice, but three fucking times. Once, she just flat out didn't even tell him a reason. The other two times, she blew him off for two other guys.
To explain her logic, one of those guys flat out told her (and this was her freshman year in high school so it was a pretty big deal), that he was with her just to get sex out of her. So she gave him her virginity and he dumped her the next day, and she was fucking pissed. Like...what do you expect, you idiot?
She would get mad because she wasn't center of attention. She'd drop friends just because they didn't worship the ground she walked on.
This one time, I was so tired of her. I was up to my limit with her when she decided to pull a prank on me that pushed me over my limit (she touched my stuff and hid it somewhere in the lunchroom, I had to go around getting under tables that people were eating at and collect my things). That was the last time she messed with me. Confronting her about it later, she turned it around on me because I didn't find the prank nearly as funny as she did, she said "what you did was so ungodly and sinful I just can't forgive you" (logic...even hard core atheists who have never read the bible can see the hypocrisy in that one...also I didn't do anything except express my dislike for her prank by changing lunch tables)
When she was 17, she chopped off half of her hair, dyed it orange, got a hell of a lot of piercings, got engaged four times, and started dating a 45 year old to piss her parents off.
If that doesn't scream attention-seeking, I don't know what does.
Worst person I have ever met in my life.