I think your opponent might be hoping for stalemate, or more likely, just likes to say "SPARTA!" ☺
In this situation I would prefer to sacrifice the queen and then checkmate by promoting all the pawns to knights and/or bishops (unless it was a blitz game).
Why do people keep going when it's a king + queen vs. queen? I know there is a chance of a stalemate, but sometimes they keep going all of the way to checkmate. Then there are those times where they keep playing until the side with the queen has a mate in 1. The worst is when they make their last move and then resign faster than you can move the queen! I don't understand it. I'd understand it at low rating, like 600.
Yes, I'm a little annoyed. Here is the final position from my last game (following 13 turns of K+Q vs. K):
Promoting my a-pawn might have been faster.
It was sort of funny since they dramatized it by saying they're going to fall on their sword and typed "SPARTA!"