phrase usage - What do they mean with "Hi, how are you doing"?

When I was in New York the workers at the counter (in a shop) always said

Hi, how are you doing?

I was, and still am very confused if they just mean "hello", or actually want to know how I feel.

Could someone please tell me if this is just an empty phrase or if the speaker is genuinely interested.

Answer

It's just a hello, they don't actually care how you are doing. Some appropriate response would be to say

• Hello


• How are you (without actually answering)


• Fine, and yourself? (doesn't matter if you are doing fine or not)