One of the biggest areas that I encounter this is when someone asks for registered delivery.
It's been probably more than ten years since we did a service called registered mail but old habits die hard. Sadly some of our customers refuse to die, hard or otherwise.
Registered mail was replaced with special delivery but most people can't grasp this. A bloke I've just served handed me a parcel and asked for registered delivery. Out comes the usual spiel reserved for this situation:
"Do you mean recorded or special delivery?"
"I want registered post."
"We haven't done a service called registered post for years now. We can do recorded delivery or special delivery."
"I want registered post."
"There isn't a registered post any more. It's either special delivery or recorded delivery."
I described the difference in the services to him (I won't do it here cos it's dull) and told him the prices. He had to go and check with someone in the car. Two minutes later he returns:
"We want registered post please."
In the end, I just did it special delivery for two reasons. One, it's the most secure service so his parcel is very unlikely to go missing so he won't be in to bitch at me and secondly, it's the most expensive service so I earn the most from selling it. See if you can guess which of those reasons I find the most important.
On a related note, A lot of people are too tight to send important/valuable/urgent stuff using special delivery. It really narks me off as it's a missed opportunity for me to make more dough and it increases the likelihood of some twat moaning that his £300 necklace went missing in the post and he wants compensation for it.
That's why we always ask if they're sending valuable stuff and if so point out that standard post is only covered up to £39 if it gets lost/damaged. We'll invariably ask if they can send it recorded delivery but we then have to point out that recorded is only covered up to £39 too. Usually they'll say something along the lines of "Oh, that'll do" and send it off like that.
Similar applies to documents and passports. You wouldn't want them going missing in the post so we always recommend special delivery. Especially for passports as it's fucking obvious when there's a passport in an envelope. If you send an item special delivery then it's tracked everywhere it goes so if a dodgy postie pinches it, it's traceable to that postie. Normal mail and even recorded mail isn't trackable so any postie can nick it and there's no proof. And let's face it, all posties are a bunch of thieving bastards so you have to take precautions.
Frankly, if I weren't so honest, I'd have made a fortune in nicking valuable stuff and selling stolen passports and almost certainly getting away with it.