Ha Ji Won - I disliked this person on sight the first time I ever saw her in a movie. I find her acting very fake, without substance and annoying. I'm often shocked by how popular she is ... which I presume is because she plays all these supposedly 'badass' characters, but give her a role that doesn't require her to wield a sword and spit fire with her eyes and she's out of her element - then she only knows how to whine/cry and act like a spoiled brat. Extremely overrated. She's also one of those people who come across so pretentious in her interviews. Like she's not revealing her true self. To me it always seems like she's putting on an act or wearing a mask when I watch her on reality TV, interviews, press cons etc. She just doesn't strike me as sincere. I dislike her so much that I've blacklisted the vast majority of dramas or movie she's in.
Park Shin Hye - another overrated actress I don't like. As a matter of fact, she's like the younger version of Ha Ji Won. Hard for me to class them with the word 'actress', because to me neither of them are. PSH also strikes me as fake & insincere when I watch her in real life contexts. I don't think she's beautiful either, like everyone always says. Her nose looks like it has been broken in several different places and never quite healed properly. I'm guessing botched plastic surgery.
Kim Tæ Hee and Moon Geun Young - both have really weird, childlike faces. I don't dislike them, per se, but their childish features make it hard for me to find their characters believable, esp in shows where they have a love line.
Lee Jung Suk - Wow, do I dislike this guy. His 'acting' is atrocious and his face gives me the creeps. I can't believe how many people go crazy over this guy, all that plastic surgery makes him look like an apparition ... but oh well, to each their own.