JANEWAY: Gentlemen, welcome aboard Voyager.
KIM: Thank you, sir.
JANEWAY: Mister Kim, at ease before you sprain something. Ensign, despite Starfleet protocol, I don't like being addressed as sir.
KIM: I'm sorry, ma'am.
JANEWAY: Ma'am is acceptable in a crunch, but I prefer Captain.
Voy, Caretaker