Washingtonians love to use the wonderfully passive aggressive phrase "excuse me!". Sometimes (occasionally) it seems to be 'excuse me, I am sorry, I was in your way', sometimes (slightly more often) it means 'I'm sorry - I know we both have every right to occupy this space, but I wonder if you wouldn't mind if I occupy it momentarily' and pretty often it seems to mean 'I've not really given any consideration as to whether or not either you or I are behaving acceptably, but I want to occupy the space in which you are currently situated so f**k off out of my way'. Often you can tell from the tone of voice which one it is, but not always. It is like a reflex many Washingonians seem to have (by Washingtonians I mean people who have lived here for a while). Of course, even when it is actually pretty rude, you can't exactly point it out to someone since (a) no one really seems to notice they are doing it and (b) what is rude about 'excuse me' ?
Anyway, here is a wonderful example of it happening to me a few weeks ago (the entire rest of the pavement and road are both empty)::
A few seconds later:
His immediate reaction is to say 'excuse me!' in an accusative tone. I do apologise, sir. I will try to be a little more considerate of you next time.