I think saying saying "how are you", and not meaning it, is rude.
I'm not Mr. Manners but even Emily Post in her 1922 Etiquette guide says,
"Informal greetings are almost as limited as formal, but not quite; for besides saying “How do you do?” you can say “Good morning” and on occasions “How are you?”
I'm never sure how to respond when someone says, "how are you?" and there isn't any real connection, time, or expectation that you would say anything real back.
I could say "fine" and "how are you?" The problem is I generally won't mean it - so I generally won't say it. Certainly there are times - fairly rare I'd think - where we really want to know how someone is.
I'm thinking about situations where people say "how are you" the same as you would say "hello" or "good morning". It's not a question so much as a statement (except it is a question which tends to just confuse the recipient). Oftentimes it's in a context where you have a few seconds to respond because you are both busy and need to move on. It's also often in a public setting where someone is (hopefully) unlikely to say how they are.
I think saying "how are you" in a situation where someone could not respond only lessens our ability to communicate. To me saying "how are you" and not meaning it, is communicating that I don't really care how you are, but I'm willing to say words that sound like I might.
Depending on the tone of the person saying "how are you" it can be an aggressive sort of statement - you better be fine, because I don't have time to hear how you are. It's also an aggressive sort of statement when phrased as a question - because it demands a specific response. A simple "good morning" or "hi Jack" or "hi Jill" doesn't demand a specific answer.
When people say "how are you" to me I generally respond "fine" and maybe "thanks for asking". I don't respond back "how are you?"
Why?
Because if I see you walking by me in the hall or on the street; I don't have time to hear how you are. So I won't ask.
I will ask "how are you?", but only if you have time to talk and I have time to listen...otherwise a nice "hi Bill", "hello", "heh", "good morning", "good night" or whatever words are somewhat spontaneous and thoughtul seem more appropriate to me.
It's all about tone though. Some people can say "how are you" and you can tell by their tone and body language that it's a nice greeting. For people who yell "how are you?" to everyone they see, like a command...well...they should read Emily.
And if you really want to know how I am - or I want to know how you are - then let's sit down and talk.
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Postscript - I know some things just become automatic to people and they don't really hear what they are saying, or think about what they are writing (certainly the case for this blog).
I sometimes find myself using the words, "thanks" or "thank you" - way to much. I used to sign off a lot of emails with thank you...or end phone calls with thank you. I know it's phony..but I can't help it. I am a pretty thankful guy. But when someone calls me and asks me to do something and I end the conversation with "thank you" I think it might be a tad confusing...or at least is watering down the English language a little. For my part I'll try to say thank you when I mean it.
I sometimes find myself using the words, "thanks" or "thank you" - way to much. I used to sign off a lot of emails with thank you...or end phone calls with thank you. I know it's phony..but I can't help it. I am a pretty thankful guy. But when someone calls me and asks me to do something and I end the conversation with "thank you" I think it might be a tad confusing...or at least is watering down the English language a little. For my part I'll try to say thank you when I mean it.