Let me just put this out there : if you're walking through a door and you let it swing closed behind you without so much as a glance over your shoulder to see if anyone is there? You're an asshole (and I don't care if you're a man or a woman, btw).
It really is that simple. Unlike so many other areas of our lives that are filled with nuance and shades of gray, this is delightfully, blissfully clear: Asshole, or Not Asshole. No latitude, no margin for error, no wiggle room. No extra thought or analysis required.
I was originally going to elaborate on this, maybe even rant a little. But you know what? Not necessary; the moral of the story is plain and obvious:
Pay attention. Don't be an asshole*.
* I recognize that this advice/philosophy is applicable in a wide range of situations and aspects of life, but I prefer to keep my expectations reasonable (i.e. low). It's all about choosing your battles, people.