Why does he keep smiling at me?

Like today I was power walking my way to my sociology class which he and I share. As I opened the door to the building I looked back to see if there was anyone behind me so I can know whether to hold the door open long enough to let them catch it and as I looked back he was here and he instantly smiled at me. I paid no mind to it because there was a girl in between us. But as we were both going upstairs and I tried to look over him to check the clock he flashed me a bright smile again. When class was over and I made my way to the shuttle bus. When I got on he was sitting in one of the front rows and again as I began to walk down the isle to look for a empty seat he smiled at me again. But that time I didn't realize until I sat down a row or two behind him and noticed that his head was following the direction I had just walked.

Why does he keep smiling at me? Is he trying to be nice? Does he want to be friends?
Why does he keep smiling at me?
Post Opinion