I work in a Post Office and am often amazed at the stories my customers tell me. One afternoon last week a lady brought in a parcel saying 'I can post it now I've found the post code for the address it's being sent to'. I said that we don't need the post code, we can try and look it up (doesn't always work with the daft Post Office system), but it is only advisory not compulsary to put a post code on. It turns out that she'd gone to a different Post Office in the morning who'd refused to take it with no post code. Now that is sheer laziness as she was sending it standard parcel and we have to input the address (post code and house number) into the computer. Without a post code we have to put the full address, so for the sake of typing in a couple of extra lines of address they refused to take it!
It would be lovely if all Post Office clerks were not tarred with the same brush, but there are some p*llocks out there.