Is it always appropriate to reciprocate when asked "How are you?" [closed]

This question is related to When someone asks how are you, are you supposed to answer, "Good," or "Fine," and ask back?. There, the answer by z7sg Ѫ claims it is sometimes appropriate not to reciprocate when asked "How are you?". I guess the following situation would fall under the category of "being asked by a shop assistant":

A little while ago I was visiting a US agency in a European country. There was an American man at a counter serving people. Each time a new person came in, the man would greet him/her with something like "Hi, how are you?" and a smile. Most people responded with just "good" or "fine". When my turn came, I responded with "I'm fine, thank you. How are you?". I could see the man was a bit surprised, but quickly recovered and replied he is doing fine.

When someone asks you "How are you?", he is probably not genuinely interested in how exactly are you doing. Why is it then not appropriate always to ask the same question back, or is it? Can it sometimes be too friendly?

Solution 1:

A nice rule of thumb is:

Consider the situation. Does the person asking have time to listen to your reply? If yes, go ahead, if no, they probably don't have really have time to reply to you either, and thus for you to ask will be to them an inconvenience although a kind one at that.

... and one for the other thumb:

If when asked "How are you?" you mean to reciprocate, it is best to do so with a different more unique question, like "Not too bad, how about yourself?" or perhaps even better "Not too bad, how about yourself? I sure like the new display on aisle 5". A unique question shows sincerity and genuine interest, each of which will warrant the shop keeper the time to reply, and give him a topic to talk about, so he doesn't have to come up with one on the spot.

Solution 2:

According to an example in Cambridge Dictionary if you find it a bit boring to always reciprocate "How are you", you can say, sometimes, "Hello Steve" or "Good morning Mister Smith". And smile.

Solution 3:

I would say it is appropriate to not ask back when the real question is not "how are you?" In the case of the shop assistant, for example, the real questions is "can I help you?" and it helps them avoid seeming too pushy. Or, at the doctor's office, it's "what's wrong with you?"

Solution 4:

Politeness and etiquettes have spurned the rise of expressions and words, whose action and intent differs quite a bit. For example, expressions such as "see you soon" are widely used to conclude an interaction but rarely signal any intent to see one another again.

Using the same token, "how are you" falls in the same category.

However, exceptions do arise based on the tone of the person's voice, duration of eye-contact, etc; intuitive factors which are more indicative of one's intent.