Mommy Confessions ~~ Manners = Uppity?

This morning, I'm scratching my head about something.  I'm hoping someone can enlighten me or help me out with this one.  Here is the scenario.

Last night about 8ish, I headed to the grocery store that's right around the corner from my house.  It's smaller, with smaller aisles, so you DO have to wait for someone to move to the side before you can proceed down an aisle.  I have no problem with this.  I actually like it because it causes people to interact and not just think about themselves (that's a whole other topic though).  I finish gathering the items I need and head to the check lanes.  I check out and had 3 bags plus a gallon of milk.  No reason to push a whole cart out of the store for that.  So, I return the cart to its "home" and begin toward the door.  Right about then a lady comes rushing through the in door and runs smack into the bags I was carrying, almost knocking them out of my hands.  I looked up and said "I'm sorry, pardon me."  Her reply "Get out of my way you uppity b-word".  Um, what?  How does apologizing for something and saying excuse me mean I'm an uppity b?  Was she offended that I actually HAVE manners?  I really don't get it. 

The thing is, I've been called something like this before.  At the same store.  It just really bothered me that I would get called a name for using manners.  Is the world really that rude a place these days?  I don't live under a rock or anything, but I also don't allow my family to get away with rude behavior.  Oh, I just don't know.  Maybe I AM and uppity b and just don't know it....HAHAHA.

Advice?  Insight?