Not a text but an email.
Was sent a group email by a guy who ran a sports club at uni setting out the team for the first half of term. It included a complete prick who I didn't see eye to eye with, and who was seeing my ex, which was all still very raw. There were strong suggestions, which turned out to be true, that he'd made a move on her while we were still together, which contributed strongly to mine and my mates' suspicions that he was a dickhead.
I replied to the guy running the club to say 'look, I don't like this guy, there's been all these issues and I don't fancy training with him two or three times a week, let alone competitions etc, I'm not that fussed and I'll drop out' (it was my last term at uni and frankly I had more important things to focus on).
Accidentally replied all. To everyone in the club, including the guy and the rest of the team, and the ex. Felt awful after I'd done it to be honest, whatever our differences it was not a very polite thing to do and was embarassing for all. Had to send a follow up to the guy running the club and apologise to the guy I'd had the issues with, which wasn't much fun.
You live and learn. I laugh about it now.