Do you aggresively play out situations before they happen?

I find myself playing out situations in my head aggressively before they even happen. I never act on them but it drives me nuts that I do this and make myself angry. It's mostly when I'm commuting in the morning to work and people are pushing/shoving to get on the train. I've been pushed by men before trying to get onto the train and have even pushed back while speaking up just to prove a point that it's not OK. I'm a petite person and I realize everyone is in the "rush" but gees, have some manners. I hate that I act so defensively but is it human nature or something to worry about?