I can't get it right. If someone sits beside me on the bus, it pisses me off that they have encroached on my personal space, and I steadfastly refuse to close my knees .
But if they walk past me, I take personal offense. I've tried smiling, I've tried looking them in the eye as they walk down the aisle. Or I'll studiously look away. It doesn't matter. They don't sit beside me. Which I realize is a good thing. But it's a bit of a shot to the self esteem.