[S]econd thoughts tend to be tentative, and people tend not to believe that they are being lied to. Their own fairmindedness makes them gullible. Upon hearing two versions of any story, the natural reaction of any casual listener is to assume both versions are slanted to favor their side, and that the truth is perhaps somewhere in the middle. So if I falsely accuse an innocent group of ten people of wrongdoing, the average bystander, if he later hears my false accusation disputed, will assume that five or six of the people are guilty, rather than assume I lied and admit that he was deceived.
That reminds me of http://xkcd.com/690/.
Also:
If one group of editors were to say the Earth is flat and another group were to say it is round, it would not benefit Wikipedia for the groups to compromise and say the Earth is shaped like a calzone.
(Quoting this before dinner is making me hungry.)
Another monthly installment of the rationality quotes thread. The usual rules apply: