I personally am pretty shy with people, then get more talkative. This guy I met a few months ago was very talkative and outgoing the first few interactions I had with him; now he seems extremely shy and awkward around me. He blushes and touches his face and ears constantly. I don't think I did anything weird, so why is he being so strange now? He has a girlfriend and it's not like I'm flirting with him! I can't tell if he developed some kind of crush on me or it's just his personality.
I've also caught him looking at me from the corner of his eye multiple times. I feel like he does this quite often, I'm just too chicken to look at him.