I should have punted her backpack across the aisle

Yesterday, on the 5:10, there were 2 seats left on the coach I hopped on just before the train closed its doors. One lady took one and I took the remaining one.

The woman sitting across from me had her large, blue backpack in front of her feet giving me no room to put my feet in front of me. This left me to sit awkwardly with my legs spread wide, similar to a sitting birthing position.

It wasn't a ladylike position so I politely asked if she would move her backpack to under her seat. She told me it wouldn't fit. I said it probably would. She said perhaps I may want to sit somewhere else? Then she sucked her teeth and looked pointedly around her with a "Can you believe this b*tch?" expression on her face.

I didn't even hide that I was taking photos. Eventually, I brought my feet together and pushed them under her backpack. She didn't like that and gave me a dirty look. I buried my head into my book.

When she got off at Ajax, the woman beside me told me this woman actually had her backpack on the seat I was sitting on and that she had asked her to move it.

She apologized saying she probably put her in a bad mood before I got on.

This I don't understand. Why in the hell do people lose their marbles over someone asking them to be courteous? When did this become a problem?

Generally people are pretty good about moving items when asked. People who are not must be hardcore car commuters who can't believe they're on a commuter train because their car broke down where, god forbid, they have to share space.