yes i too have suffered muppetcourieritis it seems to affect their ability to read, or leave a note. for instance when the collection instructions say, "package in the back garden, you would kind of hope that a normal person would go through the gate a pick it up. but no they don't read that bit. and then put a card in telling you that you weren't there.
talk about stating the f"ing obvious, i know i wasn't there, thats why i put the package in the back garden
took them a week to work it out