A grocer put up a sign that read, "Eggplants, 25 cents each - 3 for a dollar."
All day long, customers came in exclaiming, "Don't be ridiculous! I should get four eggplants for a dollar!"
Meekly the grocer would capitulate and package four eggplants.
The tailor next door watched this going on all day and finally asked the grocer, "Aren't you going to fix the mistake on your sign?"
"What mistake?" the grocer asked. "Before I put up that sign, no one ever bought more than one eggplant."