I think this is actually a really good drama. The storyline is basic and it's more of a daily life kind of plotline it's still interesting. Sometimes these kinds of stories are refreshing to watch, without all the drama and thrill and intensity. Sometimes it's nice to relax and watch a show about average lives and growing up.
The cast has some top-notch actors/actresses so it's all done really well; although the characters are just simple people I think sometimes that can be harder to portray than an over-the-top kind of character or one that's written to be a precise way.

The music/OST is average but it's not bad either.

The rewatch value is high for me. While the surprise at the end would be ruined (although you pretty much can guess the ending by midway anyway). The rewatch value of just relaxing and watching these characters grow and relive their teenage years is reall high. It's easy to just watch it again and not stress about anything, and probably have some nostalgia of your own.