Grandma trash

so i was driving home from work today and as i was merging over to the left lane and minding my own business i hear all this honking and realize that i am totally cutting off this 70 year old lady with the ball of white hair and im about to run her beat up car off the road. I swerve back in my lane and feel terrible for scaring this old lady to death. Well i end up getting in front of her but i turn around in my car and try my best to motion "im sorry" to her without words. (which is actually not as easy as it sounds.) So at the next traffic light she slams on her gas and i can see her coming up beside me. I am thinking oh good i can say sorry now or possibly get a scolding from an old lady. She pulls up right beside me, slows down with her windows down. I look over to apologize and she is shooting me a bird and screaming "you bitch" over and over. All i can do is start laughing. Who taught Grannie that word and more importantly why isnt she at home baking cookies?