twist of fait accomplis

I finished The Picture of Dorian Gray last night and was looking through some of the LibraryThing reviews of the book and came across this gem:

This is a mystery story. This book was interesting because it showed also dirty parts which people have. I was surprised at the unforeseen ending.

My thoughts:

1. It's not a mystery story.
2. "Dirty parts which people have"?!!
3. Unforeseen endings are surprising by nature.