As stated I felt many of the other commenters were way too quick to judge this manga and quite nitpicky. The beginning can feel as if too much information is thrown at you at once and is disjointed. It is also rather slow to pick up speed, so that can be a turn off to some. However, this is by no means a slowly paced story and I feel as though things happen in a reasonable manner and there is enough little twists and turns (albeit random at times) that make this an exciting, fun read. I'd say the biggest flaw is the gaps that occur as the webtoon progresses and minor things are left unexplained at first, but eventually these smaller events will be weaved back into the main storyline and serve their purpose. (As of finishing Ch121 this is consistently true so far) Some of the character's mindsets and attitudes can be frustrating, but come from completely justifiable places, and THEY HAVE FLAWS FOR A REASON. I mean this would be an incredibly boring read if everyone was perfect and happy-go-lucky from the get go. Character development and story progression is why we stay.
Now onto the things I love about this series:
1. Characters are properly developed and continuously developed as the story progresses. Not just that, the author has gracefully added adorable, humourous quirks to all the characters making them perfectly shoujo-esque. The reason I read mangas/webtoons/manhuas is for these adorable quirks that is often absent in Western media. This also makes all the characters more lovable and *real* to an extent.
2. IT'S SO FUNNY. This series (again) has that oddball humour that I only find in East Asian media, yet it doesn't take away from the story. It's tastefully sprinkled here and there keeping things light and fun.
3. Both main leads are amazing. Both strong and smart, yet not without their flaws. They are likeable and make it very easy to root for them.
4. This isn't a linear story. Despite the amazing wit of people on the 'good' side, their seemingly perfect planning is thwarted by an almost equally witty 'bad' side or simply because life happens. It's exciting and keeps you on your toes.
5. It's charming. Interactions between characters on all fronts is unique and refreshing. All sorts of personalities clash and ebb, so much so even the filler content is a joy to read.
All in all, this isn't the perfect story, it's by no means the Game of Thrones (the books) of shoujo webtoons. BUT, what elevates it to a 8.5 is that it perfectly exhibits all the lovely elements that make a shoujo good. Exciting, refreshing, fun, yet solemn and serious at times. Definitely worth a read.