This is one of the most original plot lines i have ever seen. Normally it's popular guy falls for unpopular girl, not saying it isnt but, in dramas like that the girl has to changed herself. One thing I loved about this one is that the girl didn't physically change one bit, she just became more matured, and the boy liked her inside and outside, from the very begging till the very end.
The character development from the FL, was just spot on. It's almost perfect.
I´m looking forward to kdramas where the female lead doesn't become "prettier", because why should the boy or girl become prettier just for someone. That´s just messed up. I need more kdramas where the character actually focuses on their character development.