First of all, this is the love story between a handsome alien and a beautiful human girl which is an actress. Secondly, the storyline is interesting because before this I didn't see any romance drama which is related to an alien and a human, so it's interesting to me. Thirdly, their acting is too excellent. You can't find any wrong in their acting. It looks like they are really in relationships. Fourthly, I think Kim Soo Hyun is the most suitable actor to act Do Min Joon because of his cool face (without smiling, if he smile, he will become a sunshine boy????) nobody can replace him. Finally, this drama makes me laugh a lot of time because of them when both of them are interaction (The two main character).