What does it mean when a guy stares and smiles into a girls eyes and.....?

So the other day I was at the store, this is his third time doing this actually, ...I was just standing there laughing and smiling with my cousins, and then,This boy ped by me, and we locked eyes, I was smiling and he was smiling, we were doing this about a good 5 mins, !and then there was another time when me and my friend were at a baseball game, he stopped in front of everyone, and was staring and smiling at me, when he stares at me, its almost like he is hypnotized or something, anyway,what does it mean?,=)