The cast was excellent! Yoo Seung-ho as Kang Bok-soo was terrific. Yes, I thought he went overboard on the anger aspect of his character but his love for Soo-jung was a treat to watch, his deep voice pulls you right in, and that smile! Jo Bo-ah as Son Soo-jung was lovely. First, she's stunningly beautiful. I actually liked her more as a teenager, because the adult Soo-jung was kind of a mess. Kim Mi-kyung as Bok-soo's mom, she's the mom that we all want. Kim-Yeo-kim as Oh Se-ho's mom, yikes! That character was an absolute nightmare and she played it perfectly. I had seen her as a sweet character in Terrius Behind Me, so to see her as this evil, cutthroat character who would stomp over her own son to protect herself was a revelation. I had seen all the previously-mentioned people in other things, was impressed before and continue to be impressed; however, Kwak Dong-yeon as Oh se-ho was new to me and this acting was spot on! The intense stares and the sudden evil smiles actually gave me goose bumps! He was the kind of evil that is difficult to watch, but then when they had flashbacks you could feel his loneliness and vulnerability. Then, later in the show, when he wasn't quite so creepy, I enjoyed watching him so much that I'm going to see what else he's been in. I hope that in the future he gets tapped for the male lead that is a cold CEO and meets his match, he'd be perfect. everyone that played the students were very good and I liked the way friendships were forged.
Chemistry - the kisses between the leads were wonderful. No open-eyed fish kisses. And there's a little added excitement when there is a danger of them being discovered.
Storyline - implausible, but I was willing to suspend disbelief. The problem, for me, came in the writing and the way it was executed. It went on entirely too long and there were so many things going on that they were never completely and fully able to address any of them. It flitted from one problem to another. After 32 episodes, the ending felt rushed (as so many K-dramas seem to, unfortunately). And I'll be honest, once they redeemed Oh Se-ho, I was disappointed that he wasn't with the other main characters at the end, with their friendship renewed.
I was glad I watched it, but it's not something I would re-watch, because it was too long.