I can't think of my drill sergeant as anything but ma'am*. see frightened us so much that everyone would slip with the sir. If you fumbled and tried to recover she would yell at you more, you just said "sir" or "ma'am" with confidence it seemed not to matter. I rather would have a 6'-5", muscle building, drill sergeant than her any day. She was flat out mean, We kinda thought she had to compensate for her size and sex. **
* Anytime I get frustrated about arguing with my wife, I think about being yelled at for 6+ weeks, from a 5 foot petite women I could not stand, and think "Life is good."
**When a drill sergeant says, "I don't want to hear, I don't know. Make up anything. Say a freaking pink elephant did it," Don't actually say "a pink elephant did it."