Oh my-you are so right, I have often been a little confused to this "how are you?" as well, because sometimes when people ask me, they actually walk away in the middle of it, their back is turned while I stutter my answer. Now I just don't answer when I know that it is a formal way to make little conversation, or if I know it is a way to say "I don't have time to chat, but I have to be polite". It is actually insulting. SO yeah, I agree, if you are indifferent to a person's answer to that question, a smile and a hello will do just fine!