I can see why this is beloved by many people. If it were one of my first K-dramas, it would've been a feel-good one for me too.
I really liked the male lead, he was the perfect boyfriend! The female lead was goofy and fun, albeit immature. I didn't like how the whole triangle was done though. I felt ML and FL had enough going on themselves in their personal lives, I really don't know why the second leads and triangles were necessary. Speaking of, I honestly got a Second lead syndrome, but for female lol. I felt sorry for her; in another story, she could've easily been the MC. There was so much heartbreak between the ML and her and so much potential for a second-chance romance. She felt out of place here! I don't know what they were trying to do with all the flashbacks between them, if not make us feel sad and nostalgic for them together.
Not to mention on the other side, the FL had a thing for ML's brother for 10 episodes before anything turned around. I thought the focus should've been on ML and FL more, not on other characters.
It's a solid 7/10 for me.