What is the third most frequently asked question by new people you meet after 'what is your name' and 'what do you do'?

"Where are you from?"

Why is it so important for people to know which community, region you belong to? 
And the excitement to find out that you belong to the same community is something that baffles me completely.

"Oh you are also Punjabi. Wow. Great. So am I".
"Oh so you are also Bengali_________" and then rest of the conversation is in Bengali as Hindi is not to be used ever again.

We do we feel scared of differences and feel comfortable in similarities in a country which is nothing but full of diversities?