Have you ever given directions to a four-year old?
“Go to the end of the hall and turn left,” you say.
“Is this left?” he asks, holding up his left hand.
“Right!” you say cheerily.
He then lowers his left hand and puts up his right hand.
“Oh,” he says, “Then I have to turn this way.”
“No, no. That’s your right hand,” you say. “The other one was your left hand.”
The poor kid is now totally confused. His mind, focused on left and right, didn’t grasp the changed context of your initial response; he missed that you had switched from right/left to correct/incorrect, or, in other words, right/wrong.
I experienced a similar e-mail exchange the other day on a newsgroup I belong to.