I made it a rule to forbear all direct contradictions to the sentiments of others, and all positive assertion of my own. I even forbade myself the use of every word or expression in the language that imported a fixed opinion, such as “certainly”, “undoubtedly”, etc. I adopted instead of them “I conceive”, “I apprehend”, or “I imagine” a thing to be so or so; or “so it appears to me at present”. When another asserted something that I thought an error, I denied myself the pleasure of contradicting him abruptly, and of showing him immediately some absurdity in his proposition. In answering I began by observing that in certain cases or circumstances his opinion would be right, but in the present case there appeared or seemed to me some difference, etc. I soon found the advantage of this change in my manner; the conversations I engaged in went on more pleasantly. The modest way in which I proposed my opinions procured them a readier reception and less contradiction. I had less mortification when I was found to be in the wrong, and I more easily prevailed with others to give up their mistakes and join with me when I happened to be in the right.
~ The Autobiography of Benjamin Franklin