I'm very happy to say I've never been the recipient of one of these. According to Wikipedia, these often mean-spirited postcards were first produced in America in the 1840s. Known as ‘Vinegar Valentines’ they were once very popular among those who liked to tease and poke fun of others.
I can only imagine how Miss Bennett felt when this landed on the mat on Valentines Day 1912.
Happy Valentine's Day.
May all your cards be pretty ones.