When I made a special trip to the post office to get the international stamps, they told me they couldn't sell them to me that day. They had the stamps right there, but their scanner was messed up and not reading the correct price, and they couldn't possibly just sell me some at the correct price without using the scanner. Nor could they post this temporary prohibition somewhere near the entrance. Much better that I should wait my turn in line so that I could hear about the problem from them in person. A brief Grinch moment in an otherwise happy day...