How do we address stranger in Indonesia?

Honorific Based on my experience and observation.

Addressing people in Indonesia is sooo tricky... As Indonesia know to be a country with quite language diversity, the way you address people different from one to other place. Most of the time we use 'Mas' for Male, 'Mbak' for female. But in some place they believe that the honorific title only reserved for Javanese. "I'm not Javanese don't call me with that tittle." *akward*

Basically to address people we must consider age and gender. It's impolite to call someone older only by his name. Calling name only reserved for same age friends, people younger, and your pets (and calf). If he is much-much older that he could be your daddy or generally he is unfit to be your older brother, you call him 'Bapak' or 'Pak', If she older, as old as your mom or even more you call her 'Ibu' or 'Bu'. So you must choose carefully between 'Pak' and 'Mas' or 'Bu' and 'Mbak'. Because well all like to be though younger than our actual age.

When I was in high school, We had a journalistic workshop held by a journalist. He is javanesse, he address each single of us with 'mas' and 'mbak'. He is much older than us, why he address us with a term reserved for people older. I felt a little bit weird and suggest him to call us by our name. Most of the time older people address us with 'dik' or 'dek'  a short version of 'adik' (lit. Little sister/ brother). But according to him, in his believe they address everyone with 'mbak' and 'mas' as a polite ways to address someone he just met. It's most like a formal form to address people you've just know.