I won't say hate because they both seem to be good people, but I'd say Lee Jae Yoon (Another Miss Oh; Weightlifting Fairy KBJ) and Park Shin Hye. 

I have the whole ass list for that but in general I dislike those Kpop Idols turned actors/actresses....Don't come @me ..Just because they acted ( It is rather blank stares , smile, laughs, cries )in few  of their MVs for split seconds.. they think they are actor now...leave that job for actors/actresses...Many deserving actors and actresses have to manage being supporting cast  just because some Idols thought "acting is their cup of Tea". Their dumb fan hypes them and bring ratings which in turn makes dramamakers  to bring them more....

park. shin. hye.

literally cant stand her at all in any drama

I don't hate any actors or actresses but..

I don't like Kim Goeun, Park Shinhye, Gongyoo, Jang Geunsuk, Park Boyoung, Park Sodam etc.

Can anyone explain what exactly an idol is? Is an idol a kind of singer/dancer in a kpop group or something? 

 alon-luna:

Can anyone explain what exactly an idol is? Is an idol a kind of singer/dancer in a kpop group or something? 

Yes

Boys: Yoon Sang Hyun.... definitely the one I dislike the most (but I wouldn't say "hate"), I also don't really like Jang Geun Suk (but it was way worst before)

Girls:  Yoona but again "no hate", I just think that she can't act, but as a singer I kinda like her

 gaurij:

Yes

That makes sense. I can see now why it’s such a bad idea to automatically give a hard role to them without letting them try a supporting role first 

Park shin Heye.
I know nothing about her personal life or anything, but I just hate her acting.

She makes to many weird faces and mouths in any drama she acts . It's so sad when I'm about to watch something and I read ''Park Shin Heye'' as main role '-'

I drop it before it starts 

 NONAME:

I have the whole ass list for that but in general I dislike those Kpop Idols turned actors/actresses....Don't come @me ..Just because they acted ( It is rather blank stares , smile, laughs, cries )in few  of their MVs for split seconds.. they think they are actor now...leave that job for actors/actresses...Many deserving actors and actresses have to manage being supporting cast  just because some Idols thought "acting is their cup of Tea". Their dumb fan hypes them and bring ratings which in turn makes dramamakers  to bring them more....

baek in Scarlet Heart acted pretty decent ;-; 

Besides, this is market, and names are brands, known brands, sell more, that's the way world works

Gong Seung Yeon.
I dislike her way of acting, and also  her roles make me like her even less

Kim Hye Ok.

I can't stand when she starts her high pitch screaming and dramatics...I either have to skip the scene or put it on mute. Sometimes I'll completely skip a drama that looks pretty good because she is in it. Damn Banshee! 

Hate is strong word but I dislike Shin SeKyung

I dislike Lee Jong Suk's acting.. He's playing same characters all the time, same mimic, same way of speaking, same mannerism. In my opinion he's overrated and one of the worst trending actors in Korea right now. I think his best performance was in movie V.I.P because it was totally out of box for him. I hope he gets more roles like that and then maybe I'll change my mind (like it happened to me in case of  Yoo Ah In's acting).