Show me yours and I'll show you mine.

So, I was at a touristy spot called Casa de Fruta yesterday. I was taking a picture of some vintage farm implements and equipment. While taking a picture of a tractor a woman said to me, "Just say, "show me your tits, for fuck sake!"." I kid you not. There was literally nobody anywhere near where I was shooting. There was nobody to the front or sides of me. She assumed that because she was walking from behind me in the direction that I was shooting, that she was the REAL reason I chose to shoot my subject....so that she could walk in frame about a full minute after I started shooting.
I am the first to admit that I love the female form. I will admit I love nude photography, especially when I can do a shoot in a renaissance style. Having said that, why would she assume I was trying to shoot HER form, especially when she was no where near, and I was done shooting when she walked up? Are some people that desperate for assurance?
I'm not the greatest person on the planet, but I'm not a douche either. If I want to take a picture of the person in question, I ask. I think from now on, my response to an ego-maniacal person like her will just be a childish, "If you show me yours, I'll show you mine."  That way, they'll have something to go home and bitch about. lol