I just finished this masterpice. To be honest I had some doubts about it and my main reason to watch it was IU.
I wish i had watched this before; the story overall is so beautiful and heartwarming. It truly points out how the relationships we build in our life can drawn us or save us.
Every character develops in such a beautiful way. It can seems slow at the begining and probably it´s not made for everyone tastes, but you should give it a try. Every day life and the difficulties that comes with it can make really wonderful stories.