Just smile and say it sweetly

Guy behind me repeatedly walks into my backpack as we slowly move forward in crowded Long Island Rail Road train car aisle at 1AM, trying to shove me along, despite the fact there are people in front of me and I can't go anywhere.  I've had a 14.5-hour work day on set, most of which was spent on my feet in 3-inch heels outside dressed in winter wear in 80-degree sunny weather.  So I'm cranky, thirsty, overheated, tired, and in no mood for disrespectful jerks:

Me, turning around to him after he walked into me again: I can't go anywhere.

Him: That's okay.

Me, sweetly: Oh, you misunderstand.  I'm not apologizing.  I'm saying back off and stop shoving me.

He did.