1) Why do we say "Hey there?" to people? It makes no sense, as it's usually used when walking towards someone. Technically you're using the same area. Shouldn't it be, "Hey here?"
2) What about "Hey you?" I think they "you" is implied. No one ever says, "Hey me."
3) For that matter, why do we say "Hello" at all? Isn't that implied too? Yes, Hello. Can we move on now?