SPOILER ALERT!
The show was overall a good one up until the last episode. The whole time the show was giving the message that we should accept life's challenges and smile through our troubles. The ending ruined everything. It was sad when Jun's mother told Ra-ra that he was dead, and it was hard not to cry with the scenes where each one of Jun's friends in Eunpo, especially Ra-ra, were grieving about his passing, reminiscing good times with him, and trying to make sense of his sudden loss and his choice to hide his illness from them. Nobody wanted the love story of Jun and Ra-ra to end that way. But it would have been better if he remained dead. There is nothing heartwarming about a dead loved-one showing up after 5 years saying, "Hey, I'm alive!! I just waited until I'm well before I told you!" Making somebody you love think that you are dead is just heartless, and IT IS deception, pure and simple. He deceived everybody who ever cared for him.
First he deceived them when he told them he was studying abroad when in fact he was sick, and then again when he let them believe he was dead when he was trying to fight his disease. And the viewers were also deceived by this plot twist!! Just because the writers wanted the viewers to feel good at the end, making a dead person come to life again and giving this shallow reason why he lied is just not good writing at all. It would have been better to show Ra-ra moving on with life despite the devastation Jun's death brought her because that has been the message of the story since the start. This is the worst ending I've seen among all the kdramas I have watched. What a disappointment!