What if your walking down a hallway and a guy stares at you?

There could be a lot of explanations for this. Do you dress weird? Is your hair a neon color? Maybe he's a stalker, or he might just be odd.

Best way to solve that mystery might be to ask around and see if anyone knows anything. Or you could just go up and ask him. "Hey, why are you staring at me all the time? Do you like me or do I have food stuck in my teeth?"