When You Tripe A Letter

If your friend, acquaintance, or unknown appears to have made an error, consider the multiple causes for it?  They were unfamiliar with the facts (ignorance), they had been misapprised of the situation (duped, for any of the reasons), have the wrong facts at hand (stupid), or being intentionally deceitful (evil).

Without mentioning the last, unless it comes to blows, give the error-prone a choice.