Problem: The PointyHairedBoss asks for a delivery date for some work that you know is next to impossible to meet. You ask him which features he wishes to include and he says, of course, "All of them."
Solution: You stick out your hands and say, "Count the number of hands you see in front of you. Multiply that number by <unit time> for each of the features you asked for. That's when the results will be ready."
I have actually used these very words with clients who were so wilfully dense that they needed such treatment -- or a smack upside the head with a TwoByFour.
See also: GuessTheNumber, DeathMarch, IwantaPony