A teenagely, weepy, naive story. Although starting out rather good it quickly deteriorated into uninteresting, like unfortunately many Korean dramas nowadays.
Main male actor has no character. The other two main male actors have much more charisma.
In Korean dramas the person contesting for the "heroines" love often like in this drama depicted as someone she can hardly stand. It makes the story very one sided. Reality isn't just black and white. Most of the times it's just different shades of grey...
Don't know how can be so popular. Think it's mainly because the female lead used to be a "cute" child star.