I love this drama so much, it has so many levels, to the point I wanted to main leads to get their way out and win, even though they were "bad". To do that Seo Min Hee had to die, and I wouldn't mind, at the end of the series she was getting on my nerves (she decied to sell her body, but wasn't prepared to deal with the consequences putting people in danger,being selfish) plus the officer (she was doing her job so well) but it just got in my nerves.

The cop seemed to mean well, but she was always "a day late and a dollar short" (as are most cops - thus it's good to protect yourself in whatever way you think is best).  Mr.  Lee was a great badass but human character and Gyuri was a 9.9 out of 10 in a school girl uniform.  The only missed plot twist could have been some dialogue where Gyuri volunteers to work as a prostitute or the kidnappers threaten to force her to work in the trade (waitress, hostess etc.).  Is it realistic that a high school girl would want to get into the pumping business?  No matter how capable, intelligent, and rebellious she may be, it sounds unrealistic.  Of course, the whole premise is unrealistic.  A thug is going to take orders from a phone?  How does he know it's not a cop?

YES, she was a horrible character. So selfish, contradictory, hypocritical, rude and evil. I know she had a trauma and that is understandable, but her actions were just awful. She got what she deserved.