I was walking to the shop earlier today and my path crossed with this cute girl. I was staring in her direction, so it appearead as if I was looking at her. She then began to smile at me. I noticed her smile and then locked my eyes with her with this semi-serious concentrated look on my face, almost as if I was in deep thought, pretty common across most introverts. She smiled for some time but I just stared at her. When I got to the shop I just started laughing, a cute girl smiled at me. I had an easy chance but didn't even know how to smile back, I don't know why I didn't. How can I get a natural smile going when I'm walking acround the street and see a cute girl, in fact doesn't even need to be a cute girl. Smiling at everyone portrays a pleasant image. I feel as if I cannot react in time as the window of opportunity to form a smile from a serious face is too small. When you walk past someone it is a mere second encounter.