Checkout Line Assh*le

I was at Busch's the other day paying for some odds and ends. When I went to sign my receipt I stumbled a bit over my own feet -- I'm clumsy! It happens! -- and steadied myself by putting my hand on the bagging area. It landed next to the purse of the woman who had paid before me and was still bagging her stuff. I don't know if she thought I was trying to cut in front of her, push her, steal her purse, cop a feel, or really what I did that was so offensive to her...but she got right in my face and goes "THAT WAS VERY RUDE, YOU KNOW." I was completely taken aback. I wish I could say I rose to the occasion, but I couldn't think of a good response...all I said was "Um, SORRY?!" in sort of a teenager I'm-totally-not-sorry-and-we-both-know-it sort of way. I wish I had kicked her in the shins.