4x13 - Pepper Ann

Now, on the eve of Valentine's Day, Pepper Ann's haunted by 3 ghosts, they show her how she tried to get her parents together by forging each other's names on cards, and when Lydia gave her a necklace. Then she sees her friends at the dance missing her, then she sees that if she doesn't learn to love Valentine's Day, she'll be a lonely old lady who forbid it. So she vows to love Valentine's Day forever.