And why? 

What k-drama was so awful that you did not bother to see more of?

The Heirs : no story (dropped after 13 ep.)
Pretty Boy : way too overacted to my taste (1 ep.)
Mary Stayed Out All Night : I couldn't stand the fact that they made drunk people look like something funny / cool (2 ep.)

Also with a rating of 5/10 because they were just boring to me : Cruel City (2 ep.), Thousand Years of Love (7 ep.) and Night Watchman's Journal (4 ep.)
I dropped a bunch of dramas but those 5 are the one I rated the lowest and I still remember why.
Dream high it was very boring :(
I haven't dropped any k-drama yet, but it fun to see what you guys think and why you dropped the drama. 
I dropped many.. last one was Cinderella and Four Knights.