You know what really bothers me? When people don't say hi. Or they don't even have to say hi, but they could at least acknowledge your presence. Just a smile. Eye contact. Let you know that they know you're there. That you aren't invisible.
Like today, I was walking to my computer tech class when I walked past a girl I know. I wouldn't really say we're friends, but I know her name, and she knows mine. We've had a few classes and conversations together. As I walked past I looked at her and smiled, but instead of smiling back she looked away. Sad.
But then I passed someone else I know as I walked into the classroom and he smiled. And waved. And said "Hi Dani."
I love it when that happens.