Man, without commas we'd all be screwed because, not only do commas stop sentences from running on, but they help connect phrases that would not normally be considered sentences. Thanks, commas.
"hand over the commas"
"we'll include yo mama, if you fuck with my commas" - Ice Cube
Also, synonym for period.
John: Yeah man I heard she was on her comma.
Jack: Wanna have sex when we get home from wally world?
Jill: I can't. I am on my comma today.
Girl #2: That's hot but damn girl, ain't you on your period?
Girl #1: Hell no hunny, that was two days ago! I'm on my comma now.
Girl #2: Well shit, that's a different story then. So what'd you do?
Girl #1: I took him home with me, what else?