Yoona's friend from elementary school revealed some shocking secrets about her on KBS Sweet Night. The members of SNSD came on Sweet Night to celebrate their comeback and they were greeted by friends, a teacher, a delivery man and an old time crush on the corner, "Sweet Acquaintance, It's been a while." In this corner, Yoona reunited with two friends that she lost contact with from about a decade ago. The friends revealed an incident where their teacher told them to pick someone as their partner and write the top three candidates on a piece of paper. The teacher ripped up all of the papers afterwards and Yoona went through the garbage to figure out which boys put her name on it. She also had the hobby of going into the boys bathrooms - scandalous! Her friends also stated that the three of them would constantly play Gostop, Korea's version of poker. "When YoonA was in third grade, she loved playing Go-Stop. She was so good at it that I thought she was a gambler," one friend revealed. One time that the girls were playing, they heard someone approaching. "YoonA instinctively covered the game with a blanket and put it in the closet. I didn't realize that she could be so fast." So this girl was gambling all the while visiting the boys bathrooms. Didn't know Yoona had it in her. Having SNSD on the show, definitely helped out Sweet Night because the viewer rating was bumped up to 12.7% for this episode.