"These are my birthday shoes!"

"What do you mean? They were a gift?"

"No, never received a gift in my life; these are my birthday shoes!"

"You never received a gift?"

"Well, I once got a gift certificate but I don't consider that a meaningful gift--there's no thought in it."

"Sure there's thought in it--namely, 'this whole rigamarole is not as inherently meaningful as it is that you get something you want. your pleasure is more important than your being flattered by my thoughtfulness.'

"Oh, that's a lot of hooey. Time is money so you can subtract from the overall value of the gift certificate the cost of my time."

"So you're sayng that the measure of a gift's thoughtfulness is its cash value."

"Listen, bub, you gonna buy my birthday shoes or not?!?"

"How much?"

"20"

"10"

"Sold!"