I'm conflicted about this one. I did like it and watched it quickly (it does only have 8 episodes) so I was invested, but the concept of the Love Alarm app and how it impacts the characters and their society was what interested me the most (Black Mirror is shaking). I really liked the friendships as well and how it briefly talked about homosexuality and how such an app outed people against their will. But the romance didn't make sense to me. At all.

From Jojo's point of view, it's normal, but as viewers, we know that Sun Oh only knows that Jojo exists because Hye Young likes her. It feels like the only reason he tries to seduce her is because his best friend likes her, he probably wouldn't have noticed her at all otherwise. So, it doesn't make sense to me... and it's also a dick move. The friendship between him and Hye Young is obviously strong, but it looks like Hye Young is the only one actually doing anything for Sun Oh. Everytime Hye Young decides to do something for himself (like twice during the show lol), Sun Oh gets mad. It sometimes felt like the main relationship of the show was between them, to be honest, and it probably would have been better (a love triangle I could get behind, for once). Because, aside from his behaviour, I do not dislike Sun Oh that much. But he's a selfish baby, sometimes.
There's not much to say about Jojo, she's a cliché, but the way her best friend treated her was really disappointing. Her friend could learn from Hye Young.

I have Thoughts about the Love Alarm app but that would include too many spoilers, but I really want to see how it's going to be treated in the next season and if someone is going to do something about it or not.

This being said, I wasn't rooting for Hye Young until the time skip. I mean, he's a sweet boy but it's not like he ever talked to Jojo. I definitely am not rooting for Sun Oh, though, so as much as I'm curious about the Love Alarm app side of the plot, the romance and how it might "evolve" doesn't make me that excited for a second season.