Russell Roberts' account of this exchange with a sidewalk artist makes me feel all warm and tingly inside:
I gave him a $20. He handed me the change and said, "We're even."
I smiled and said, on the contrary, we have a beautiful picture and you have our money to enjoy as you wish. We're not even. We're both better off.
It sounds horribly pedantic on paper, like an English teacher telling him he'd used 'hopefully' in the wrong way. But he smiled and said, you're right.
But of course we were even in another way. We were both better off.