U Wook grew up acting like some rich boy in a kdrama. He was ambitious and cunning. He would find something he wanted and then he wouldn't let anything stand in the way of him getting whatever it was. He was fine with sneaking around with other rich boys to have fun. They wouldn't tell anyone because it would disgrace their families if anyone knew. If anyone did decide they didn't like the way he behaved he would lie his way out of it or find a way to keep them silent. He was good at getting people to fall for him and he took advantage of that. When his family went to America that aspect only got worse. He had enough variety that he didn't have the chance to get bored. Then he met Andy. After Andy nothing was the same.

U Wook avoided relationships back home because in would involve him telling them all about what had happened and why he now had to make trips to the doctor often and to take medication. He turned his attention to pursuing his new dream. New sides of his personality slowly started to poke through. He used the same ambition to push him into training and he worked as hard as possible to catch up to the other trainees so he could be considered for debut eventually. Even when he started to become exhausted easily he would hide it and tell everyone that it was fine. He wasn't used to people worrying about him so why start now?

He eventually realized that he was far more compassionate than he had ever imagined. As he got close to people he couldn't help but want them to have the happiest life they could. Instead of thinking how hard life was he decided he wanted to do everything he could to make life a little better for other people. Sometimes they just needed to know someone was there for them and at times that's all he wanted as well. He rarely used his cunning nature unless someone truly deserved it. His behavior in the past caused him to have a hard time trusting people. He knew that they weren't always what the appeared to be and he refused to let those people get away with hurting the people he cared about. This led to him becoming rather crude. He would tell people exactly what he thought of them and if they didn't get the hint to leave he would resort to making them leave. He was also unafraid to talk to people about basically anything that they could thing of. He didn't skip around the subject of physical relationships. He realized that it could be dangerous to not have anyone to advise you on these subjects.

U Wook was rather single minded and this could help when it led to him focusing on improving his life, but for the most part it caused him to be distant from people because he was too busy focusing on working. It was hard for him to bond with people because he couldn't take his mind off of improvement so he seemed unapproachable. It did contribute to his unending loyalty. He would do anything for a friend if they were in need and he wouldn't let them suffer alone. He did his best to stay out of friendships with people that weren't at all interested in him to some extent.

He wanted to be able to be more open with people and to be honest about everything, but he couldn't bring himself to tell others about his HIV. He couldn't handle the thought of others judging him for the choices he made. He didn't think there was anything wrong with fooling around with people as long as no one got hurt. But the thing was, he did get hurt. He was punished for one bad decision with a disease that would never really go away. He was stuck with this reminder for the rest of his life. He couldn't enter into relationships lightly because he would have to tell them and worry about their health. He wouldn't be able to stand himself if he gave HIV to someone he loved. So he tends to be secretive about himself. He keeps certain things hidden especially his visits to the doctor. He can't bring himself to be open about it yet so he hides his pills in areas that he figures no one will like in so they won't ask him about it.

When he steps on stage he lets his inner charm shine through. He loves to interact with the fans and to give them a good show. He's been known to help them down the stage or to put on a little extra aegyo if they request it. He shines in front of strangers since he's fairly good at getting people to see what they want to see. He has no problem with saying that the fans are his girl friend or saying his ideal type is someone who loves him. Anything that gives them a little more hope. He wants them to get a feeling of love from him even if they just meet him for a few minutes.