Usually if you are talking to a guy and another one is staring unhappily at that guy it's either one of three reasons. One he likes you. Two kind of ties into one he cares for you but doesn't trust either you or the guy so he's making sure you two aren't flirting. Or three he just flat out doesn't like that guy and it has absolutely nothing to do about you.
He likes you.
it means he like you or he's into u give it a shot
It means he need to see a physician. He needs to get a life!
He is shy around you! He likes you a lot but to scared to say anything.
Most likely
He probably thinks you are beautiful,as all girls are.
He probably likes you too
i would think it means hes jealous and doesnt approve of you talking to another guy
Either the guy is interested in that girl, or he just was interested in what she was saying.
IT MEANS you passed through his mind at least once a day.! =)
He wants to get in your pants.
He must like you, to be staring at you. Either that or he's admiring your eyes, but seriously what guy does that?