As I enter I hear a grunting noise.
I quietly enter my stall and close the door to handle my business.
As I pluck the @$$ saver from it's dispenser to cover the seat I hear the woman next to me grunt and then apologetically explain,
Excuse me, I'm taking a Boo-Boo.
The voice sounded raspy and distracted by her current activity.
Before I began my business I simply replied as cheerfully and quizzically,
No need to apologize. We're all human.
and finished my nature call.
I quickly washed my hands and over the running water continued to hear the grunts and heavy breathing (that thankfully was not accompanied by any scent whatsoever).
I found her innocence puzzling.
The public restroom is not a place where I normally apologize for the goings on, or interact, actually. It's a place where I put up an invisible wall in addition to the one separating one stall from mine. You go in alone and leave alone, and maybe say hello to someone on the way out.
But not in the middle of a nature call.