Search & Missing: the Other Side, they had potential but ended up being boring for me

The Mentalist - I'm not sure how close they follow the original with the scriptwriting but if they follow the same script I warn you about major plot holes and idiotic behavior of characters

Call boy - Not a drama but it was so boring and lacking in sense of depths, while playing around with important and serious topics, i couldn't even finish it lmao

The school nurse files : Unless you've got nothing to watch and have 6hrs of time to spend watching something weird and like wack it's not that worth a watch. 

The Great Seducer: Tbh Dohwan is one of my fav actors but I srsly couldn't sit through the drama. From the posters and teasers, I expected some dark stuff. Instead, this drama ended up being kinda cliche. Most of the actors did their parts really well, but that couldn't cover up the fact that the plot was messy and frustrating.

Why R U?:  Had a visually-pleasing cast, romantic and cute scenes, steamy kisses.........but........BASIC PLOT. There's literally nothing happening half of the time. The leads feel attracted to each other, deny their feelings which is followed by a weird 'push n pull(?)' attempts by them. Just dragging the plot. They finally get together,,,,,,,and then starts the "fan-service". I had to skip scenes as their storyline wasn't going forward. Its as if they didnt have any more conflicts to fill the series, so they just ended it all with filler beach scenes. The storyline of the second couple was *slightly better* than the leads' tho

God's Gift: 14 Days - didn't watch this but I read spoilers about the ending being unsatisfying 

Cheese in the Trap - I removed the drama from my list after reading that the main leads relationship could be considered toxic, apparently the ML is not very likeable 

Minami-kun no Koibito - My Little Lover: the acting was very awkward and cringry to me, especially that of the Female Lead. She screamed or talked loud a lot of times and my ears are still bleeding :') Nakagawa Taishi, who plays the ML is eyecandy to look at, but that's about it. He didn't have much of a personality in his character in this one, which was sad cause he is a really good actor!

Meteor Garden - it's rather unrealistic and cringy 

The Advisors Alliance - have not watched it but it seems to be draggy (as read in comments)

Soul Mechanic  - havent completed it but I think Jung So Min has done better drama that are worth the watch compared to Soul Mechanic.

Kill Me Heal Me - FL was really loud and obnoxious.

I've also been a bit disappointed in Chicago Typewriter (though I still have 3 episodes left). I've just found it rather boring.

Watashi wo Hanasanaide - I like the story and watched the movie/read the book but couldn't get into this drama version

The Dude in Me - one of the most boring movies I've watched, if you like body switching movies I recommend the Japanese movie Reon instead. Daddy You Daughter Me was a bit better than The Dude in Me.. 

Kimi ga Kokoro ni Sumitsuita :  I frankly thought it was quite boring, and I didn't feel any chemistry between the leads. The FL sufferes from social anxiety I believe, so ofcourse she will act in certain ways, but at times it was just very annoying to watch. She had the potential to grow but that just.. didn't really happen, which was disappointing