Guam or the Post Office??

Today I received a notice from the post office that I had a letter that needed more postage before they would delivery it to me. After I handed over my sixty-eight cents, the post office worker bent over and started to mess with some things in his drawer.

It took me a few seconds to realize that he was pulling stamps out. He proceeded to put sixty-eight cents worth of stamps on the envelope, then he stamped the postmark over them before he handed my my letter.

Uh....why? What a waste of time - his and mine - and a waste of perfectly good stamps! Why in the world did he need to put stamps on a envelope that is not going through the mail??!!!

Not sure if it's a Guam thing or a post office thing, but whatever, it was very odd.