At work we have a black & white copier/printer and a color copier/printer. We had gotten in the habit of sending a lot of our black/white things to the color copier (which is nicer), but we needed to curb that behavior to extend the copier's life.
One morning this week I went into the copy room and I saw some new teachers in the room who were using the color copier for their black and white items. I kindly explained the copier differences, they warmly received it, and we all carried on. A couple hours later I see one of the same teachers back using the color copier for her black/white copies. I say, "oh, are those black and white copies?" To which I get a response of, "YES. But they are going on COLORED paper."
(silence; thoughts racing of "how do I not sound like a smart-*%& in respondingto this" and "really?!")
Finally, me, "color paper goes in both."
Then I ran to the other program assistant offices to share the story.