So I like this guy. I've never really talked to him but he seems great. Whenever I see him we make eye contact and I've even got a flirty smile from him recently. Somedays I think he notices me and then other days I don't think he does. I'm afraid to talk to him for the last three months unless I needed his help with something and then we often make eye contact and he acts as if he's waiting for me to say something? How can I tell if he's interested?