To sum it up - because it's so busy all over the place, no actual point gets made and it ends up feeling like a waste of time. Some scenes go on and on unnecessarily and feels rather random. As a viewer, you find yourself bounced from one story line to another but nothing actually gets told in a way that would make a proper impact.
I'm not sure if it's because of the poor directing or story, but the lead, Lee Jun Ho doesn't make an impression on me. Whereas Jang Hyuk is awesome but I feel like his character could have been used more effectively to make the story more compelling. Jung Ryeo Won is lovely but I'm not really feeling her character either despite knowing she's meant to be the heart of the story.
I'm not one to drop a drama no matter how bad it is, but this bad story telling is making me want to drop it (after all, it's 38 episodes!) - nonetheless, it does get better in the latter half (around e25 onwards), but it really took a long time to get there.