A basic greeting:

Hello World!

My kids in the back seat

A long, drawn out salutation:

Ah! Oh my goodness! What a delightful surprise. I am so glad to see you. I was just thinking of how long it has been since we saw one another last!

 

A less socialy refined acknowledgment:

Huh?

A poseur acting formal:

Greetings! Brilliant! Yes... Hmph. Quite! And to what do I owe the honor?