Trying hard to be sociable

Most people initiate conversations with a question. Some of them ask multiple ones to stretch a conversation. Yet some, jump to the next question before you've finished answering the first. I know two such people in my life. I don't understand them.

Bumped into Person 1 on a busy street. 

Person 1: How was your trip to South Africa?

Me: Oh it was wonderful. Very very scenic and....

Person 1: Oh my driver has come. See you around. 

Bumped into Person 2 at a party.

Person 2: Hey, how you doing?

Me: Good and you?

Reva who was with me: (smile)

Person 2: How was  your trip?

Me: Great. Hows wor....

Person 2: How are you Reva?

Reva: I've been ...

Person 2: So why don't we get a drink?

Me: Sure, what do you....

Person 2: (To someone else he just spotted) Hey, how are the folks? Catch you two later :D