At least in USA/Canada, it is a greeting not intended to solicit any true information. This changes the question to a genuinely caring one, which is generally not the intent.
In Malay, the equivalent is "What news (do you bring)?" and the generic response is "good news". And if someone is not doing well, the response might be "things are alright".
But it's a bit more useful IMO because people can just say anything they like, e.g. "I got 2 hours of sleep last night!" or "I haven't had lunch. Want to eat together?"
When I lived in Costa Rica, I think they used to ask in Spanish, "ÂżCĂłmo amaneciĂł?" [0] and then when I lived in Tanzania, they used to ask in Swahili, "Umeamkaje?" [1], which both roughly translate into "How did you sleep?" I believe.
[0]: https://forum.wordreference.com/threads/%C2%BFc%C3%B3mo-aman...
[1]: https://www.reddit.com/r/swahili/comments/ze6cj5/when_would_...
Agreed. How are you in American culture tends to not elicit any sort of personal information (i.e. think about how many times people say "good"). Something significantly more specific like 'how did you sleep' or 'what have you been thinking about" get to the essence of our original question of how the other person is.
It seems much more Thought-Provoking, for sure!
The Novelty alone would make me stop and think about my response. Or a similar lifestyle-probing question, like "How was your Dinner last night?"
For sure if it's a parent. I never had one good night of sleep since son was born, literally.
How’d you sleep ;) jk but seriously this would only sound reasonable before the hour of noon
Instead of "how are you?" I prefer "how are you feeling?"
sounds too personal and HR will probably won't like this question
Yes, it's a little invasive.
How did you sleep is a great question to understand how someone is, it’s one of the first things I ask myself when I wake up. I then get a more quantitive answer from my Oura ring. That then helps me plan what is achievable that day.
BUT, “how are you?” is almost always a Phatic Expression[0], especially in cases where it could be considered a generic greeting.
Phatic Expressions seem to be more important to some cultures than others. For example, in Australia it’s such a fundamental greeting it often trips people up[2]. In this case the question is not a genuine or sincere inquiry into you current state, but rather a request to acknowledge the presence of each other.
In that sense, “how did you sleep” would be such a curve ball unless among friends I think it would cause secondhand embarrassment.
Tom Scott did a great 3 min video[1] on this exact thing.
[0] https://en.wikipedia.org/wiki/Phatic_expression [1] https://www.youtube.com/watch?v=eGnH0KAXhCw [2] https://www.unilodge.com.au/blog/g-day-mate-a-guide-to-aussi...