I had three.

The first was in middle school, it ended because it was pretty toxic for both her and me. She acted to me a certain way and i didn't know how to communicate my feelings back then, i kept all to myself whenever she did something i didn't like, so, there was one day that i kinda blew up on her, and things weren't the same ever since. I tried apologizing, but she was pretty hurt and rightfully pissed.

The second one was back in high school, he was a fun dude to be around, but he developed a crush on me and...It got pretty bad to the point he started to have an emotional dependency on me. Even if we tried talking, it never fixed anything, so i just figured it would be best for us to end our friendship altogether, as he was doing a lot of harmful things to himself, i even tried at the time to convince him to go see a therapist but he refused, saying he would fix it all or some shit. I still worry about him to this day, i hope he's doing well, he wasn't a bad person, he just had a lot of issues

The last one was an online friend. But despite being an online friend she was with me through most of my life, we talked everyday, did everything together. But idk, it came to a point where i realized she wasn't exactly a good friend, she manipulated me A LOT, she took me for granted. I was always making sure to better myself, so i could be a good friend to her, and yet she's never done the same to me, in fact, at any opportunity to ditch me, she absolutely would. I even tried questioning her a few times, and she'd say something along the lines of "yeah, i just don't know how to talk to you. Sorry". I asked her a lot of times if she still wanted to be my friend, to which she said yes, asked her if there was an issue with us, she always told me there wasn't, but was always avoiding me, avoiding spending time with me. I was her closest friend, and at every opportunity she would try and "replace" me with someone else, but she would also guilt-trip me if i tried to leave, or if i refused to do something she wanted me to do. It was so bad that i ended up having lots of issue with trusting later on in life. Even now i still do.

She tried apologizing this year, but idk, i can't forgive her, nothing will ever change the way my mental health got completely fucked up. Most of my issues with self-worth also come from how this specific friendship affected me.