The Driving Insane

Without preamble a mail carrier in a dirty uniform says:
"What I'm looking for is a 2007 calendar showing the full moons."
Here I have a list of the dates. Will that work?
"Well, I really need a calendar. Don't you have anything like that in the library?"
Most likely, everything we have will just be in a list form like this. We don't have our 2007 calendars yet.
"What I really need is a calendar."
[The other librarian suggested he go buy his own calendar and write in the dates we had given him.]