You hit the nail on the head when you said "customer disservice".I've seen myself going into shops and getting that look like I'm bothering them, you know by asking a question or otherwise making them do their job.

As for bagging groceries, I hate doing it. That being said, I usually end up doing it myself because the cashiers here have no idea what they're doing. IThe last time I remember a cashier packing my groceries , she yelled at me because I had the audacity to stop her from tossing my chicken in a bag with some produce (ummm, raw chicken...with other stuff, ick). In light of that, I figure I'm just better off doing it myself.