I would have to say the couple's mask because of the deep NPC development, and also really felt as if I were there in the room with Anju waiting for Kafei, that final 6 hours music really sunk in and I felt as if I would actually die in the room with them. SO SAD!
For some reason this quest really made me feel for the characters, so definitely this mask.
![Kawaii :kawaii: :kawaii:](/forum/styles/default/xenforo/smilies/kawaii.gif)