Market design in particular is an outward facing part of economics, and much of what needs to be accomplished requires economists to play a helping role. So I've always liked the sentiment in the title of this post, whose origins turn out to be (fittingly) hard to attribute. Quote Investigator looks into it and finds many early origins and variations.
 A man may do an immense deal of good, if he does not care who gets the credit for it.
 This was the opportunity for a man who likes to do a good thing in accordance with the noble maxim … “Never mind who gets the credit.”
 The way to get things done is not to mind who gets the credit of doing them.
 There is no limit to what a man can do who does not care who gains the credit for it.