A virtue

There is a culture in Malaysia and among Chinese in Asia: people will call an elder person either sister or brother, or aunt or uncle, depending on their relative ages. That is a manner or respect, even though they are not related. 

It is a virtue that most Chinese are proud of; something parents begin to teach their kids when they start learning to talk. For example, the parents would teach the kids to call their friend Brother/Sister XX or Uncle/Aunty XX when they meet.

If the younger knows the elder’s name, the younger would take initiative to call the elder Brother/Sister XX or Uncle/Aunt XX instead of hi or hello. 

And it is not very good manners to ask someone older what his/her name is at the first meeting. 

A lot of times, you would hear someone call someone uncle or aunty in public like in a store.   

In the USA, when two strangers first meet, they will tell each other their names or ask what your name is. And most, even when they know each other or are related, they just say hi or hello.

亞洲的華人及馬來西亞人，有一种文化，是對年紀大的長輩，即使不是親人，都會視其年齡相差階層來稱呼對方為姐或哥、姨或叔、婆或伯，以表示禮貌尊敬。

這是大多數華人引以為傲的美德。我相信那是從小會說話那天開始的家教，比如父母的朋友來拜訪或在街上碰到，父母都會教孩子稱呼聲其朋友為 XX姐／哥或XX姨／叔。

如果年少者知道年長者的名字，年少者會主動先打招呼叫聲年長者為 XX姐／哥或XX姨／叔。

據禮儀，初會面長者，就問其姓名，是有些不敬的。

很多時候，你會在公共場所如商店，某人稱呼某人為阿姨／叔。

在美國，兩位陌生人初見面，他們各告訴其姓名或問叫什麼名。而且大多數，彼此認識或是親人，都只說嗨。