Random Pet Peeve - Standing on the Left

I guess it's wrong for me to assume that everyone knows the "stay on right, pass on left" rule. When I encounter cars like that on the road, it's only very mildly annoying to me. But on an escalator during rush hour when we commuters are trying to get to a train and the person standing on the left side is oblivious to the long line of people forming behind him/her? THAT is annoying. Thanks for making me miss my train by a few seconds, you asshole.