Come to think of it, Fiona being cursed by the witch, to become an ugly ogre (depending on a certain point of view in an eye of the beholder, since looks are and can be subjective) at night, really connects to what she says about her tragic backstory.

“It's a spell. (sigh) When I was a little girl, a witch cast a spell on me. Every night I become this. This horrible, ugly beast!”

Which makes anyone/any viewer feel genuinely sorry for Fiona. Poor girl.