Who are you?
I love learning language because it's interesting and meaningful.
Who are you?
Who am I?
Who are you to ask me who I am?
Does that mean you want to start a fight with me?
From these, you may guess that the person who you are talking to is from North of China, right? Because in Northern China, most people are honest and direct to the point, they don't to guess the meaning behind the words, the just say it directly and they prefer action rather than words.
But if the situation will change to another situation.
"Who are you" and that person may reply "Oh, I'm Jenna -J-E-N-N-A then you can probably say that...that person is from South China because ...because the lack of enmity is noticeable by their words and also, they may understand that you are really asking ...asking "who I am" and no other meaning even if you、 yourself don't think it that way.
That's the big difference the people from South and North.
See, that's the meaning of learning language, you just don't learn the language but you also learn how to think in different ways and you can also discover the meaning behind the words.
So next time, when you try to ask " Who are you" to someone then you need to be careful how to say it because you never know how they interpret it, you never know where they are from.If you couldn't guess then just to be safe, just change your question to "May I have your name because..."