Where do I start? Haha Spoilers ahead!
Boys Over Flowers - I seriously wanted her to end up with the second lead in the Kdrama version. That is pretty bad considering my love for the anime version, which I cannot get enough of.
City Hunter -I only sat through this, because I was watching it with the friends, half falling asleep, bored out of my head. I hate when the guy pushes the girl away soooo much!
Moon Lovers: Scarlet Heart Ryeo - It's a good quality drama, but I I was annoyed with that wimp Wang So. How could he just give up on the love of his life like that???! He deserved everything that happened to him!
King2Hearts - it's pretty bad when the secondary couple is more interesting than the leads
Goblin - the romance was lame. Bad enough for me to drop it.
You Who Came From the Stars - one of the worst cases of the second lead syndrome. I hate male leads that give up on the woman they love or go hot and cold. Actually most of the dramas above( if not all) have that problem, which is one of the main reasons I didn't enjoy them as much as I could have.