On the February 29 episode of SBS's 'Same Bed Different Dreams,' the usually bright and easygoing G-Friend's Yerin turned serious and firm after listening to a mother's concern about her son who was going through teenage rebellion.  On the show, he explained that he would come in late, and if he drinks, he would not come home at all.

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Toward the son who seemed to lack any sense of guilt over his actions, Yerin said, "Everyone knows that when you leave your house, you suffer a lot.  You would not know when you're in high school.  I likewise only found out when I became twenty."

She then chided him with, "I hope that the day when you realize this will come as quickly as possible; also, do you know that what you did was wrong?" and he replied, "Yes," but she added doubtfully, "Because it looks like you don't," making Yoo Jae Suk laugh in surprise as he senses her inner displeasure. 

She might look cute, but she's a toughie on the inside!