I had this happen with a few times with guys I was talking to but most recently it is with a guy I was talking to for a 4 month. I couldn't follow through with meeting him because I was too shy. He was so open but I wasn't. Now when I see him, he just looks at me and just looks sad. Why do guys look sad at girls?
Because he liked you and wanted to get to know you more. And spend time trying to build a relationship with you.
But you didn't come through because you were shy. He doesn't know that. He's misinterpreting it as "she doesn't like me" or "she wasn't interested enough in me".
This guy took your actions the wrong way and thought that he wasn't good enough to date you. So the 'rejection' took a toll on his confidence and he feels hurt and believes that he'll never have a chance with you.
Because you couldn't follow through with meeting him in could mean a couple of different things to him. He could think you're not interested in him(rejection) or that you don't have enough character or social skills to interact with him.
I'm guessing so you feel guilt or pity. Sounds kind of unattractive to me, odd guys.
It seems that you don't show that you're interested in them a lot as well, that's why they think that their efforts are in vain and it shows on their faces.
Good lord. take responsibility for yourself. you don't just agree to meet with a guy and then not show up. that is really f***ed up. how would you like it if it happened to you? think about other people for once.