Gave me a look like I was some kind of grotesque stalker

It was my first week at the City College of New York, and I was walking to class. As I passed my the science building I noticed him, but only recognized him as a familiar face. So since he was just standing there, I introduced myself, explaining that he looked very familiar but that I just couldn't place him. He then told me that he did some shows on Nova (PBS) It all came back to me and it brought a large grin to my face. I told him that I loved his shows and was something of a fan. I kid you not, he gave me a look like I was some kind of grotesque stalker, and while staring at me, he pulled the door open behind him and WALKED BACKWARDS into the science building. The door shut and he was still backing up, looking at me through the glass. It made me feel a bit annoyed because I hadn't even gushed or anything. But I hear he's kind of a jerk sometimes so probably a lot of people have similar stories about him.