What's with the shitty face?

Look, just because I hold the door for you doesn't mean I'm trying to sleep with you! It's so lousy of you to sneer at me like I'm doing something wrong—it’s called being polite. I would hold the door for anyone walking a reasonable distance behind me, or exiting when I want to enter. I don't even expect people to say “thanks" anymore, but to actively look at me like I'm a piece of shit? Just uncalled for and it really puts me in a bad mood. —Just Trying to be Polite