“Always do right. This will gratify most people and astonish the rest.”
I’m sorry to say that I had misremembered the above quote. I thought it began: “Always tell the truth.” Even so, I’d like to think that the “truth” and the “right” are synonyms.
Here’s a page of Twain quotes twelve of which are about the truth. Some of them (the sly and cynical ones) contradict the one above.”