You're both overdressed.

"Well, I'm sorry, but I'm afraid I have to disagree again," you tell her, gesturing towards the dancing with your left hand. "You see, that party in there is for me, so I don't think it matters what I'm wearing."

"I understand, & I agree," she replies. "I also agree this is the wrong attire for that sort of party, even though it seemed fine for the one I attended earlier."

"Oh?!" you say, laughing. "The thing you were doing before was another party?!"

"What?!" she asks, stepping back slightly & raising her arms again. "You think I'd dress like this to grocery-shopping?!"

"I suppose not; No," you reply.

She steps closer to you again.

"So, since we've both done enough partying for 1 night," you ask, "what do you propose we do now?"

"Considering how I'm dressed," she replies, "I think it's only natural I accomplish some business."

"What kind of business could I possibly help you with?!" you ask her.