" The prudent man is always sincere, and feels horror at the very thought of exposing himself to the disgrace which attends upon the detection of falsehood. But though always sincere, he is not always frank and open; and though he never tells any thing but the truth, he does not always think himself bound, when not properly called upon, to tell the whole truth. As he is cautious in his actions, so he is reserved in his speech; and never rashly or unnecessarily obtrudes his opinion concerning either things or persons. "

― Adam Smith , The Theory of Moral Sentiments