Discussing economists’ reliance on measures of growth and GDP, Joel Mokyr asks:

So you go to somebody who is about to have surgery and you ask him, How much would you demand to be paid if I took out your appendix without anesthetizing you, without putting you to sleep? Nobody would agree. The sum would be infinite. What can anesthesia contribute to GDP when it was introduced in the 1850s and 1860s? Russ:Could not be very much. Guest: Nothing. It’s very small. But that is exactly the kind of thing we fail to account for in our calculations. So that’s why I gave that whole list of things; and we could make this list infinitely large. It is the small things that actually don’t amount to an awful large part of our income and product that actually have improved life a great deal and that we really wouldn’t want to do without any more.

From Russ Roberts’ interview with Mokyr at Econtalk. The quote was first brought to my attention by Arnold Kling.