Yes I have also called mam's, sir's, and sir's, mam's. Sometimes it is almost impossible to tell
But like Marlow, I also made some pax blush on a Dash. Try doing "top of decent" PA, wondering why the entire row of males in row 1 were sqirming in thier seats. I was happily wandering down the cabin doing the saftey checks when a woman in row 7 ( yes, I made it that far) tells me that I have TWO top buttons undone on my shirt. Yes, you could see EVERYTHING!
Still can not believe so many pax new, but let me walk on past.
Now I have "button phobia" and check them before each and every PA.