<my reply to another client on a print project who was asking me about the "blank space" and couldn't we put something in it>
"Just because you paying for all the paper that this is printed on doesn't mean we have to fill it all up."
One of my new favorite ones, which isn't funny in it's own right, but I'm sure everyone has heard this one:
"I'll have all the info to you by _____"
<somehow the info is always delayed by weeks, but they don't seem to think the completion date will be>