Info from WIKI
Suyeon was initially a very cold and ignorant teacher who does not care about the well-being of her students. It is implied she would even laugh at Gyuhwan when he wanted help from bullies who planted a funny picture on his back. Additionally, she was shown to be very selfish and only cared about her own survival, continually ignoring her responsibility as a teacher. She is also shown to be lazy and easily burned out, not wanting to spend time with her boyfriend after her retreat.