This younger guy has been staring at me for a while now. It usually happens from a distance and his stare is sort of serious/blank. I have caught him looking from a distance and he doesn't look away, but if I catch him staring when he is near he looks away. When I have been near him, he will watch me while I'm talking to my friends. Also, the other day we had an activity day and my friend and I were talking to one of his friends and he left his group of friends to join our conversation. He didn't say hi, he just agreed to things we were saying. However, while doing so he would look at me a lot and brush his hands through his hair. What is happening and what should I do?