But it illustrates Chicago Manual Of Style 6.38:
A comma is used to set off names or words used in direct address and informal correspondence (in formal correspondence, a colon usually follows the name).
Ms. Jones, please come in.
James, your order is ready.
I am not here, my friends, to discuss personalities.
Hello, Ms. Philips.
Dear Judy, . . .
That second to last example is the one I want to focus on. It's the comma dude in action! But sometimes the comma dude is missing, like in the examples below.
I think I can squeeze through Chief.
I think I can squeeze through, Chief.
I am not so sure I want to squeeze through Chief.
I don't mind Michael.
I don't mind, Michael.
I never mind Michael. Or anyone, really.
You know Charlie.
You know, Charlie.
Maybe I know Charlie and maybe I don't. You'll never find out.
Go on George.
Go on, George.
You want me to what on who???
A fine lieutenant? Sounds like a great start to a romance novel character.
How did you get this Dad?
How did you get this, Dad?
I got this Dad because...wait, didn't your parents explain the birds and the bees to you?
You shouldn't smoke so much Joe.
You shouldn't smoke so much, Joe.
I always drink my joe, not smoke it. Maybe I've been doing it wrong.
So please, dear author, remember where the heck you left the comma dude!