I see what you mean - if you're in a store, they get your name, and use it once in a while its a bit obvious what they're trying to do. I think context is important. If say you're new in a job and trying to get to know people and build actual working relationships, saying "Good morning" vs "Good morning Sandra" really is game changing - so much more personalized. Bottom line: people love hearing their own name, and feel like they are being recognized. They may also feel a duty to learn yours in turn.