If I were a showrunner for something like Buffy or Supernatural or any scary/fantastical show, I would always have the episode around Halloween be completely normal.
All of the characters would somehow lead perfectly mundane lives and the episode would have almost nothing…
In the Dresden Files, (books, but I’m gonna talk about it anyway) Halloween is the night when the veil between the mortal world and the Nevernever is easiest to pierce, so your regular warlocks and phages know to stay home, and only the really big players come out (and only if they’re doing something specific). Nobody who likes their organs where they are wants to meet the Hunt.
It’s also Harry Dresden’s birthday.