When confronted with this level of ignorance I will always use my cart to move the obstruction.
When confronted with a nasty word or a crappy look, I will retort,
"Whassa matter? Did I scratch your paint job?"
I was travelling all this week - today was especially exciting .... the security line at IAD went around the terminal 4Xs. It took over an hour to get through the maze. With me chanting, "THE GLAMOR OF BUSINESS TRAVEL!!!" over and over again.
And.. these three teens behind me kept bumping into me. The third time he said he was sorry and I said, "No you're not. If you were really sorry, you would stop doing it!!!"
The people in front of me laughed for ten minutes.
I HATE ECONOMY CLASS!!!!