I give "Hello! Me" the highest rating because it is one of the less than a handfull of KDramas that I watched twice and and I watched parts of Episodes 1 and 2 three times. If they are not too unrealistic, I tend to like time travel dramas but this drama has so much more.
Although it has some aspects of romance, it is not a romance drama. It has family fighting and love. And it has just the right amount of suspense. The few falshbacks are approprate. The drama doesn't have an excessive amount of flashbacks and other things just to make the drama longer. Therefore, the drama doesn't drag making you want to skip portions to get on with the story.