Chiefpriest1:
Maybe it's not disrespectful to your husband when you ask 'how are you' since you are considered 'equal partners'.

But outside close relationships, many see it as lacking courtesy.

For example, you cannot see your landlord in the morning and just ask 'how are you'.

It should be: You: good morning

Landlord: How are you?

You: Fine, thank you.

My little kids ask me 'daddy, how are' and I jokingly respond with 'fine sir, ma'.

Outside those close relationships, many consider it discourteous.

My questions are:

Is this part of our African culture or Civilization?

Are these kind of rules cast on stones?

As much as I know, culture is dynamic. As a matter of fact, it is helpful to ask the elderly (mostly aged) 'how are you'.