Sir ?

Every once in a while , this happens. . . . .. At work in Thursday I saw a man try to walk into the ladies room . Usually , it's some homeless guy calling his homeless girlfriend out because they are late for some important appointment. Last week, I even saw a woman stand at the mens room door , holding the door open , impatiently calling her man out while other men were in there using the urinals. So, I thought I was being helpful when I called out to the older man with plaid polyesther jack and khaki pants that he was going into the wrong rest room. I called out twice, once in an inquiring tone and the second more urgently "Sir? That's the ladies room!". He jerked his head back out the door, looked me right in the eye and yelled "I am a lady !" and continued on with her business.
I was embarrassed and felt bad. I wasn't questioning her sexuality. She was dressed in an ambiguous way. Her hair was gray and cut short. She had asexual silver horn rimmed glasses and she wore no make-up. Hardy Yankee ladies really let themselves go.
Fortunately, I was on my way to lunch, so I didn't have to deal with her exit.