On my way home from working out of town. I stopped at an Arby's restaurant drive through to get a snack. I used my female voice at the speaker. When I got to the window, before he looked at me, he said hello ma'am. Bad part was he changed to sir as soon as he saw me. Understandable, it was dark, so he couldn't see my makeup, I was wearing my work uniform, and my male driving glasses. I told him in my female voice he was right the first time, he apologized, and used female pronouns for the remainder of the wait.