Graphic Design: Tricks of the trade

I'm sure I've used this tactic unwittingly before: http://www.themorningnews.org/archives/how_to/tricks_of_the_trade.php

If you have a client who is unable to approve a proposed design without putting her stamp on it, just put an obvious error in the proposal: a logo that’s too large, a font that’s too small, or a few judiciously seeded typos. The client requests the change and feels she’s done her part—and your design, which was perfect all along, sails through to approval.