Every Hearts and Hooves Day has been identical for Fluttershy - alone, locked up at home, similar to Nightmare Night. But instead of just fear, she dwells on solemnity and loneliness, longing to someday feel this "love" everypony makes such a big deal of.
It started out the same for her on this Hearts and Hooves Day - until he showed up, asking for just one night with the Element of Kindness.