Do people stare at you?

Don't you think it's funny how some people stare at you for no apparent reason? It happens to me sometimes. I'll be on may way to school or work, just walking, and stare like they've never seen anyone going to school or work before. Then you say "hi!", or "how's it going?", to them and they don't say anything like they don't notice you. Keep in mind, they were just STARING!!
Then, that's where I become self conscious, like Do I look bad, or, is something on my face? Will this person get in trouble if they say hi? Are they new to this country, this state or this world? Or I am I a scientific study subject, whose habitats and behaviors should be observed for some research journal? Anyway, I just wanted to vent, because people can be irritating. Communcate with people around you. Don't stare. We're not zoo animals.