I think that awkward shuffle people do in order to avoid going first can cause irritating delays. Sometimes I think people believe that assertive people who go first all the time are being special snowflakes, when in reality, they are actually making things move faster.
I do this deliberately. I believe God put us on earth to serve one another (there's a logic fail here, actually, but let's not get into that), and one of the way I do that is by going first in the buffet line. (I used to always be first in the girls' section of the 3rd grade end-of-recess line as well, bcs I was willing to be the buffer zone betw. girls & boys.)
Going first at the door, whether you're a man or a woman--if you're going to be in the way, just go first.
People who take a seat on the subway when others are standing--if you're closest, then sitting down gets you out of the standing space with the least amount of jostling. I've seen people try to give the seat in front of them to someone else, and it takes all kinds of juggling people around while the train is moving, and it's more awkward than if they just sat down.