I got nothing.

Crowded canteen and as I put my tray back on the trolley I turn around to find a girl behind me.
"Sorry!" I say and dodge right, to get out of her way.
"Sorry!" she says, and dodges to her left to get out of my way.
Before I can say my usual quip in such situations, she dives in with:
"We're dancing!"
"Thanks for the dance!" I get in, late.
As she goes by, she adds the killer:
"I wouldn't have bothered if I'd known you were so bad."
Dang.