Most have been mentioned:
Heartstrings, end of ending episode. There is definite disgust. One would think that it were a frog that approached her, instead of Jung Jonghwa.
Heirs. The first kiss on the school terrace was a surprise and she probably didn’t even want it, she dropped her cellphone… so let’s say her reaction was somehow excusable (although she did like the guy). But the second one while hiding in his house’s closet was terrible. They are already in love, and she is not only disgusted but terrified.
You can see them both here:
“You’re Beautiful”. (Yes, that was again Park Shin Hye, the queen of worst kisses)
The Liar and his Lover. The bicycle kiss. I think it was even worse than Heartstrings, if that is ever possible. Although they do close their eyes (I don’t know if that is a good idea on a bike) otherwise it was ugh. There was also some weird contortion from the part of the male lead, in order to kiss someone seated on a bicycle behind him, and this didn’t help things.
Here are some hilarious collections:
But I’d rather concentrate on good kisses.
Another Oh Hae Young, episode 8 (end) and repeat on episode 9 (beginning). Eric was epic.
W with Lee Jeong Suk, the police station kiss.
Jealousy incarnate with Cho Jung-Seok
Anything with Yoo Seung-ho. Operation Proposal (and he was only 18 or something!!!), I Am Not a Robot…
Melting me softly. An otherwise unmemorable drama, with a very good shower kiss by the always reliable Ji Chang Wook.
I’ll Go To You When The Weather is Nice. End of ep.8, repeated on start ep.9