People who don’t read their emails properly.
Our computer system automatically sends someone an email when a book they’ve ordered has arrived. It also sends emails about once a week with an update on the order status if the book has not yet arrived. Although each email clearly states per book what the status is, quite often people don’t seem to be able to distinguish between something like “Your book has arrived and is ready to be picked up” and “This title is still on backorder”. People come in and ask to pick up a book they’ve ordered, which we then can’t find, so we have to retrieve their order from the system, and then tell them they came for nothing. Some of these people get annoyed about their time being wasted, so I’m always very careful in pointing out that they’ve misread their email (and obviously I never literally say “It’s your own fault”). But I tend to quietly get annoyed at the fact that their haste/idiocy wastes not only their time but everybody else’s as well.
Last night a girl comes in to pick up an order in the name of Bakker. I can’t find the book, so I turn to the computer to look up the order. She says she is picking it up at the request of someone else, and she doesn’t know his postcode or email address. Considering Bakker is basically the Dutch version of Smith or Jones and therefore there’s dozens of Bakkers in our system, I can’t do much without the postcode or email address. Luckily it’s a slow evening, because it takes her almost ten minutes to recover an email address from her phone. I look up the order in the system, and indeed, as I suspected, the book is not actually here, and the email never said it was. So this guy sent her all the way here for nothing. Nice going, Mr. Bakker.