I'd say (in my case anyway) that people stare because they are thinking about what they are going to have for lunch, or because they forgot to do something and are now thinking 'oh bugger'. But that could just be me, if I stare it's because I am thinking of something else, which is not exactly the best thing to do because people then ask me questions and all I can do is nod and smile blandly. However the other day I was eating in a restaurant in the window area and I got lots of staring practice in with 2 of my friends. And I can say that some people are very very odd, they stare at you and keep on walking and staring, or in the case of some strange people walk on by, then turn around, raise their eyebrows and look straight at you. I can understand the staring at some other part of someone's face (like nose or ear) if you don't want to look them in the eye, which can be kind of intimidating or confrontational, but why do people stare (who you don't know) straight at you without looking like they are thinking about their dinner? (And no its not because I'm pretty, because I'm not)