These days Valentine's Day cards are exclusively positive things, even if they're just between friends. But back before we ghosted and unfriended people, the Victorians had a special kind of card for people to say exactly how little they though of someone.
The cards were incredibly popular once though we never see such nasty messages these days, but not everyone was a fan even back then. At one point 25,000 vinegar Valentine's were held in a Chicago post office because they were considered unfit to send.
Read more about these nasty notes at Atlas Obscura