John: "For this thing we got from you, we're missing two parts."
Me: "That was delivered nearly a year ago so you're well outside the 60 day limit to report any problems. I won't be able to send it to you for free. I can ship it this way for $530 or that way for $590."
John: "I have to have it, I guess I'll get out the credit card.
Me: "Hang on a minute while I look at your order. You know, you'll need to cut out a couple of pieces of material here and here. If you do that right, you can use the material you cut out there, as the material you want to buy now. So you don't really need to buy that, you can do everything you need with what you've already got."
John: "I want to go ahead and get it anyway."
Me: "But...you know, if you want to spend money, I'll be happy to take it, but you understand that you've got enough stuff there, you don't need to get anything from me to finish your project?"
John: "Yeah, but I want to get it anyway, just to be sure."