First I want to start by saying I have nothing against anyone who was a part of this drama and this review is my opinion of the show as a whole.

Pro:
Gong Hyo Jin is so adorable in this.
Episode 9 was a rollercoaster ride for my heart.

Con:
The ghosts aren't even scary.
I was rooting more for the second leads to get together then the main leads.
Everything started to get better around episode 9.
The story and backstory felt weak and boring to a point I had to take breaks and come back when I was ready to continue.

Overall: it's not rewatchable but at least watch it once.