Goblin
Hwarang
Definitely DOTS....
Also Moonlight in the cloud.....I hate dramas about cross dressing-.- Empress Ki...I hate dramas that have hella flashbacks-__-
DoTS
Legend of the Blue Seas
City Hunter, Mary Stayed Out All Night, and Misaeng
Bel Ami. Boys over Flowers. Anything with Gong Hyo Jin. Yes, I find my bias limiting at times. 
Legend of the Blue Sea. I don't get the appeal with Jun Ji Hyun after watching You Who Came From the Star
Goblin , W , They are too overated
Love 020 is another one...I don't get why people love it so much-__-
Boys Over Flowers. Absolutely despised it. It ruined many actors for me, unfortunately. 
Scarlet Heart Ryeo just because I'd rather not watch IU act and it doesn't sound half as good as people make it sound. 
Koizora because it sounds. so. bleak. 1 Litre of Tears was amazing, but Koizora apparently includes rape and abortion and I just can't.
DOTS, I've watched an episode and hated the main couple, so I'm never touching that again.
Any drama with Gong Hyo Jin. I didn't like/couldn't finish It's Okay, That's love and somehow I came out of that drama not liking her?
Reply 1988. Watched one ep, didn't like it. Heard how it goes, definitely won't watch it.
Big. I love Gong Yoo, but I've heard nothing but terrible things about it. Clips I've seen haven't looked too great either.

Tbh I'm really picky with dramas so there's a whole bunch more.
DOTS. I'd have to force myself to see it. Dropped it after 4 or 5 episodes. 
Scarlet Heart Ryeo
I LOVED the Chinese version Scarlet Heart and was excited when the Korean version was announced but I just don't care for Lee Joon Gi -_-
Noona- donsaeng drama. Simply just not my type
Descendants of the sun and healer, i can't come to love it like everyone else does