Whats the most terrible thing a friend has done to you?

The most terrible thing my best friend has done to me is ahhhhmmmmm...many,there is this having an affair with my boyfriend,saying bad things about me when i`m not around.This was happen back when we`re still in high school but believe it or not until now she keep backstabbing on me because she think that I am her strongest competitor in the attention of our other friends. It`s just very frustrating because we`ve been best friend since we were in elementary, I cared for her for the longest time but because of her insecurities I have no choice but to end up our friendship.Hopefully she will realize her mistakes,and make the first move to talk to me coz i`m willing to reconcile with her.

yes my close friend tried to get with my ex bf that I was still in love with. And she knew it.

Yes, I actually had one just a year ago. She was real nice at the start when we began working together. We exchange food as well and stay together sometimes when we're on breaks and lunches. She even wrote a letter telling me how good I am and how friendly I was to them. I appreciated her gesture. However, a few months later. It all began. I started to hear negative things about me. Then, as I investigate, I found the root. She is. One thing that I really don't like is being a coward and not telling me right in my face what is going on and why is she acting like that towards me. She actually tried to talk some of my friends out and oppose me as well. I was her boss. I respected her as much as everyone else. But it got out of hand that she involved even people outside. I just hear a lot of thing from other people but I didn't get a good reason from her. I just had to do what I needed to do as it's affecting other people already.

This happened in high school, and no longer matters to me now (6 years later). Anyhow, a casual friend of mine (through a mutual activity) and I got closer throughout my junior year of high school. I assumed it was because we talked more, had more classes together, etc. Throughout this time I was in an on and off relationship with a guy from another school. During one of our longer "on" moments, we dated for about 3 months, but broke up for a one week period during this time. A few weeks later the friend told me that my boyfriend had cheated on me with her. For some reason I didn't get upset with her, but got really upset with him. He swore up and down that it had been during that week that we were broken up, but I believed her over him. It took a while, but through friends I realized that she had become closer friends with me to get closer to him, and that he had been truthful and she hadn't. To this day I am still good friends with him (we realized we weren't relationship material) and my friend and I no longer speak.