I apologize in advance for the scathing comments below.
I guess I have been spoiled by recent release of high quality dramas and much more improved high school C- dramas.
My personal pet peeves are lying and rudeness. The FL in this drama is extremely rude to the point of being a verbal bully as well as a pathological liar. After initial 3-4 episodes, I fast forwarded to see if there was a plausible reason for her behavior but I have never seen a flimsier excuse. Her personality undergoes minimal character growth with all the hard work of people around her. The ML is mature beyond his age but despite all that falls for the FL head over heels.
This drama had numerous characters that had grating personalities. The high schoolers failed miserably to portray some one gritty like "Extracurricular" or innocent like "Lovely us". The use of tons of make up, exhausting failure of trying to be mature, inappropriate use of back ground score, no humor or witty dialogues, led me to give it a poor review. I gave 2 points for the sweet second FL, who was the only good thing in this drama. Strong recommendations not to watch with family as children may get the wrong ideas.