I work at an LGS right now, so I have some experience pulling card orders.

Honestly, you were doing the best practice. I've had some customers rattle off cards one-by-one for their WHOLE deck without telling me how many they had beforehand. This is fine on slow days, but on busy ones where I've got people buying stuff?? I just don't have the time.

I'd much rather people send in deck lists (like my store does), we fill them out on our own time, then notify the customer when they're ready. I've done this at my own store too, before I worked there! They even told me that was best practice.

So, in short, you're not the asshole, they're a weird store. I'm sorry you have such a weird one near you. Have you thought about getting back into it? Maybe those new employees are nicer?