My no1 fake drama is definitely Boys Before Flowers. The story was full of plot-holes, the supporting actors were terrible (especially Geum Jan Di's family), the clothes were too flamboyant (oh and come on, how come Jan Di had at least 3 pairs of high heels in her little suitcase?), and Kim Joon with his english was just painful to hear. But with all of those mistakes I still think it was fun to watch.
Second place on my fake list goes to The Rooftop Prince. Although originally the story seemed very unique, the more episodes I see the more cliche it becomes. What a pity! Also half of the cast is terribly fake. I mean come on, what's up with Yong Tae Yong's family? The grandmother and the aunt are terribly played.
3rd place on my fake list goes to Startling By Each Step.
Now this drama I absolutely adore, but the fact that almost every prince fell in love with the main character seemed a bit fake. Also there were some props and places that looked horribly fake. Like these plants in the background:
Honestly, what were they thinking?
But as this drama is very dear to me, I have to defend it, for every one of the actors and actresses were absolutely great. Not one fake people among them. :)