(A customer is buying a stamp for a letter shortly after the 2007 price increase.)

Customer: “Why can’t I get a 39 cent stamp? You still have them.”

Me: “We still have them in stock, but we have to make up the difference with 2 cent stamps. Don’t worry, we’ll stick the right amount on for you.”

Customer: “I just want a 39 cent stamp.”

Me: “Okay, but your letter will not get there.”

Customer: “Just give me it!”

(The customer takes the stamp, affixes it, and tosses the letter into the slot. I promptly pick up the letter from the bin and stamp it “Insufficient Postage, Return To Sender”.)