Here are 13 of their top answers:
1."She was using my Netflix account, so I turned on parental controls so she could only watch G and PG-rated things."
2."She had been waiting for the newest installment in her favorite book series to come out for months, so I called her and left a three-word voicemail spoiling the ending before she could buy it."
3."She said I was fucking her boyfriend (who's a friend of mine). I signed her up for a cruise tour — a swingers cruise."
"Reddit and Craigslist truly have everything. 😊"
4."I bought a bunch of key chains, put his name, number, and random keys on them, and distributed them everywhere."
5."Although I feel a little bad for this now… A few years ago, my ex-best friend continuously took advantage of me, my former roommate, my money, and my kindness for over 2.5 years — stealing, lying, starting drama between my roommate and me. I let her crash on my couch and got her a job where I worked, and she did not help us with bills at all and stole our belongings regularly. I finally built up the strength to ask her to leave, and she refused and would threaten to stay even longer 'cause she can. Well, after countless texts from her bashing me, I threw all of her belongings off the balcony, sent a pic, then cleaned it up, and placed it into trash bags."
"I moved it across the street and told her to come get her stuff quickly, but apparently, she didn't make it on time and couldn't find her belongings. Til this day, she tells mutual acquaintances that she plans on fighting when she sees me, to which I'll let her get one hit off the situation.
But for the $800 dollar electric bill she racked up (A/C in winter), no shame."
6."I was best friends with a couple people. I shared one of my favorite shows with them, and we all got into it. We went to a convention to meet one of the voice actors. They basically took over the trip. We did nothing that I wanted to do myself, and when we later moved in together, they ended up being awful, toxic as hell roommates. They were even shitty to a friend I brought into the fan group, just as an extension of their negativity toward me, I guess. So the photo of us with the voice actor at the con? It was on my phone, so they can't have it. They were on one side of him, and I was on the other, so they have been permanently cropped out."
"'Cuz fuck 'em, that's why."
7."So, I found out that my friend went to the house of the guy I was dating behind my back one night, and more than likely, they hooked up. So, she got pregnant, and I found out about her going there randomly, so I told her boyfriend he needs to get a paternity test because the baby may not be his."
"Regret it, no, petty as hell, yes!"
8."We were best friends since childhood. She ghosted me for no reason at all when she moved away. She had a one night stand with a guy who was more than 15 years older and apparently thought I would judge her. Her mum told me this. I still continue to be on very good terms with her mother, and whenever we go out for a coffee, I never ask about my ex-best friend."
"This drives her crazy, according to many of our mutual friends.
I just don't think she's worth it."
9."My first ever relationship, my ex cheated on me, and my entire friend group ditched me. A year later — to the day that they ditched me — I created a group chat titled '😘,' sent screenshots of the proof I'd been holding on to that they'd all ditched me based off of a lie, and immediately left the chat."
"Now everyone knows exactly what they did wrong, and I'm living my best life with people who actually care about me and don't ditch me to hang out with an abusive ass!"
10."Her: 'If I was important enough, you would have made time to respond to my text.' Me: 'You're absolutely right.'"
11."We're both huge fans of Good Mythical Morning. One year for Christmas, they gave me a shirt that said, 'We're Still Good!' One of [Rhett and Link's] classic tags, this phrase was something we always said during our friendship when anything would happen, either between us, or if one of us was going through it. When the friendship finally dissolved, I returned everything they ever gave me in a brown paper bag and topped the pile of belongings with the neatly folded shirt with the phrase, 'We're Still Good!' facing up."
"Beautiful sign-off to the friendship."
12."My two 'friends' de facto kicked me out of our apartment, but they expected me to keep paying for the cable and internet. So I did. And I put parental controls on all their devices at random times of the day, so they'd randomly be unable to get internet."
13.And finally: "Just unadding her on Snapchat, Instagram, and even Pinterest wasn't enough, so I got rid of her mom, sister, boyfriend, and cousins on all those, too. Then I un-added her from my dog's account. I even blocked her on Spotify for the heck of it."
What's the pettiest thing you've ever done after a friendship breakup? Share your stories in the comments!
Some submissions have been edited for length/clarity.