Hearts and Hooves Day is HER holiday.
Stupid idea behind this: Ponies send her valentine/hearts n' hooves day stuff. They send her chocolates and letters and all sorts of related things, asking for her favor on this day... Never realizing of course that it is all beyond her power to actually do anything. But it makes them feel good and she loves the free stuff and ALL the love going on. Shining doesn't mind one bit, either.