f(x)'s Sulli quickly became a hot issue in the k-pop world due to her fresh and outgoing personality. Her winking smile has fluttered the hearts of the Korean teenage male population. Because she is getting so much attention at such a young age, she must have some pressure on her shoulders. In an interview, she stated, "It's so cool that whenever I do something, it comes up on the Internet right away. The thought of having many people watching over me gives me strength and encourages me." Fans have picked Sulli's smile as one of her best characteristics. Hearing this, she said, "When I smile, my left eye closes more. When we were promoting Chu~?, there was a part where I had to smile. Everyone thought that it was a wink but it automatically happens." Sulli also thanked her fans for celebrating her birthday. She said, "Thank you for always looking over me. I won't let you guys down and I will work harder."