Valentine's Day was always a sort of horror for Neville. When he was young, it had meant sickeningly pink parties with the children of his mother's friends, and now, here at Hogwarts, it meant having to avoid any shadowed corner to keep from tripping over snogging students. And of course, thanks to Neville's luck (or lack thereof), it came on a Tuesday. Tuesday meant potions. Combine two of his worst fears in life and you get Valentine's Day on a Tuesday. At least Lockhart wasn't here anymore.
For a change, though, potions started without incident. Today was a research day, so there was no cauldron to blow up, no ingredients to spill. Neville actually liked the theory behind potions, because so much of it was so similar to Herbology. Professor Snape stayed mostly behind his desk on research days. About halfway through the class, Neville noticed that Hermione, who was at the table in front of his, with Ron, was hiding a smaller book inside her potions text. Curiously, he tried to look closer. Surprisingly, it wasn't a book. It was a card. A lacy red, pink, and white card with cupids and a rather long poem inside. Ron and Hermione were both blushing furiously. Feeling a little uncomfortable, Neville looked away as they clasped hands under the table.
Suddenly, Snape stood up at the front of the class. Neville thought at first that he was glaring at him, but no. The potion master's eyes were drilling a hole through Hermione's textbook. He advanced on the pair of Gryffindors like a wraith of doom. Neville knew what was coming. He would find Hermione's card; he would read it in front of the class, making it sound as saccharine and awful as possible for the amusement of the Slytherins. Neville couldn't let that happen. Right as Snape's hand darted out of his robes to snatch Hermione's book away, he did the only thing he could think of. He whipped his wand out of his sleeves and set his own textbook on fire.
Two weeks later, when he got out of detention, Hermione gave him a Valentine's Day card and a kiss on the cheek. Yes, Valentine's Day was definitely Neville Longbottom's favorite holiday.