On the episode of KBS 2TV Wednesday/Thursday drama "Unkind Woman" broadcast on Mar. 19th, the reason was revealed why Chae Shi Ra and Suh Yi Sook had bad relations.
On this opinion, Doo Jin (played by Kim Ji Suk) introduced Moon Hak (played by Son Chang Min) to Hyun Sook (played by Chae Shi Ra). Hyun Sook asked Moon Hak why he started hating Hyun Ae (played by Suh Yi Sook) so much. Here, Moon Hak said, "In the beginning of the semester, the teacher would arrange seating based on ranking in class. I raised a flag during this which was the problem." At this, Hyun Sook said, "I wasn't good at studying and I was poor so she had disliked me. He lived in a poor house and I was asked why I was so bad at everything.
Afterwards, Hyun Sook had collected the least amount of items and Hyun Ae had thrown this out as well. Afterwards, Hyun Sook revealed that the person who had thrown her out of school was Hyun Ae. Doo Jin was incredibly surprised and could not handle this.
Meanwhile, "Unkind Woman" is about women over three generations that are not very kind. As they go through the troubles of life and love, this is a drama about trying to find happiness in society.