Yesterday I got to the outer doors of my building at about the same time as a guy.
We looked at each other, and he paused. So I reached for the handle, opened the door, and held it for him.
He said, "Thanks." and walked through to the next set of doors.
He opened one, walked through, and held it open from the other side long enough for me to catch it and go through.
Here's the thing. I totally judged him for not opening the door for me in the first place. And then I judged him again for walking through a door that was held, and not bothering to hold the next one.
I'd still find it annoying if a woman did that, but I'm sure I wouldn't judge a woman harshly.
I think this makes me sexist.