My all-time favorite korean drama

I'm just confused how my fave korean drama got 8.6 and I saw several reviews gave this awesome show a low rating. I just don't understand it. I lost count on how many times I rewatched this show because it is SO GOOD. The story, the characters, the soundtrack, the acting were all perfect so I wonder SOME gave this a low rating or maybe they are so perfectionist. For those who are new to korean drama, don't mind those who gave a low rating because they are party-poopers, don't rely on their reviews and just enjoy the show.