That's not a grammatical difference, but a situation defined by a context.
If you want to read the menu, the person who should pass it will not expect you to talk to anyone else.
If you use the pronoun, you're not being more explicit in this case, but more polite by addressing the person and distinguishing them immediately from the rest of the world.
__________________
♪ ♫ ♪ Ain't it wonderful to be alive when the Rock'n'Roll plays... ♪ ♫ ♪
|