Somehow I couldn't find any examples since I always stop reading any that use this style early on, but I realised while looking for it that it's actually Chinese not Korean that does this. To describe it basically, it's when they make the characters look disgusting by flaring their nostrils and giving them stupid facial expressions
Any manga art work that features an SJW nagging Flat-Earth mother-in-law who lives in a van down by the river with Seymour, a Chris Walken-sounding and silent film-watching vegan cannibal zombie moose.
Most yaoi, since proportions usually distract me. Heck, it was even a meme trend a while back: https://knowyourmeme.com/memes/yaoi-hand It's not a hated art, but to name a specific art (non-yaoi) I recently started reading 'Immortal, Invincible' over at Leviatan Scans. I'd been putting it off since the art was so...bad, but I ended up liking the story. The art takes some getting use to but there are still some funny panels: Sorry, I don't think I have a specific example of a manga whose art I hate
I can't stand the art style in most Shoujo manga, as it is too rosy, the lines are too thin, the art is too fluffy, rigid, and lacks soul, and that added with the uninteresting MC, cliched male characters and cliched story, made me stay away from it till now. Besides, most males dislike Shoujo manga anyway, right, so me is no exception.
There isn't a manga that I can name off the top of my head but I find that certain manhuas copy and pastes the eyes of the character so it looks like they are looking at their nose or towards the sides of their head which is very off putting. There is also this "trope" where the characters are drawn in chibi form to make the scene comedic. It is fun to read when it is timed right but when it is used constently it gets annoying. I also don't paticularly like 90s shoujo manga art styles.Sorry.