If you think the “waiting on” vs. “waiting for” argument is ridiculous, take solace in that they both at least make sense.
To this day, no one has given me a decent explanation why some people (East Coast of the U.S.) feel that it makes sense to tell time by using the phrase “fifteen of 12” vs. “fifteen until/'til 12.” 15 (minutes) until 12 is 11:45; 15 of 12 is 1.25.
I use both “waiting on” and “waiting for” but that could be because I have lived everywhere and moved so much that my dialect and accent doesn’t really have a home base anymore. 
I tend to “wait on” an event or a person (to do something). I am waiting on my husband to get home right now. I am also waiting on the arrival of a notice that I expect in the mail today.
I wait for almost everything else. I sometimes stand in line waiting for things.
In more formal situations I only ever wait for anything and forget I ever waited on it to begin with. I also only end sentences with prepositions in more casual communication, otherwise I would forget I ever “waited on” anything, full stop.
Grew up in the Appalachians but moved around a lot in a military career. Neither sounds wrong to me but I generally would use “waiting for”. Thinking about it only a few minutes in the context of this thread, the “waiting on” seems more personal in that the pending activity is for me specifically: “Waiting on my wife to pick me up” vs “Waiting for the bus”.
I personally use “waiting on” to emphasize a person or object. “I’m waiting on MY GIRLFRIEND to get dressed.” I use “waiting for” to emphasize events. “I’m waiting for the sun TO GO DOWN.”
I suppose the major difference is which part of the sentence is necessary information and which part is the extra data tacked on for completeness or filler.
I’m waiting on MY PAYCHECK to arrive.
I’m waiting for my paycheck TO CLEAR THE BANK.
But then again, maybe it has to do with being active or passive? If I said I’m waiting on Joey, you might think that Joey is holding us back from doing something (e.g. leaving a party). But if I’m waiting for Joey, then we’re standing around at the party, anticipating his arrival.
Can someone explain why that is?
Man, I swear, there are absolutely **no **country fans on the Dope. How could thisnot be the first thing you think of?
Nu-uh. It’s 180. 15 cartons of 12 eggs…
…because 15/12 is 1.25. Took me a second too.
I’m hearing it more and more, and it bothers me.
Both would confuse me. I could probably work out “until” but I wouldn’t have the faintest what “of” meant. Before? After?
Where I’m from it’s only “quarter*** to ***twelve” and “quarter past twelve”.
I must say that the only mental image I can get from “I’m waiting on [somebody]” (unless, of course, the discussion is about restaurants) is someone sitting on said person’s body, be it dead or alive, waiting for something to happen.
Same deal, I use “to” interchangeable with until or 'til.
“Of” still makes no dang sense to me, I don’t even know where that could come from and still mean what it’s supposed to mean.
Oh, and a quarter of twelve is 3 ;-).
I (living in midwest) have also heard waiting on used in the sense of waiting for, though the latter is far more common.
I have the vague impression that waiting on refers to an event which you are fairly sure is going to happen soon or at a specific time (e.g. “I’m waiting on the 2:15 train.”), and that waiting for means the event is less certain (“I’m waiting for a sign from God.”). But that seems far too subtle to be a general rule…
That’s surprising. I think I hear “waiting on” and “standing on line” from New Yorkers more than anyone else. I assumed that’s where it had originated.
^
When I hear either of them, it’s like nails down a chalkboard. It’s just like when people say, “Are you coming with?” or “Have you ever been?”
I’m from the Midwest U.S. as well, and while “on” is definitely heard a lot less than “for” around those parts, this is exactly the distinction that I’ve always assumed about the usage. This interpretation also jibes with Mick Jagger and Ray Davies’ statements:
“I’m just waiting on a friend” implies that Mick fully expects his friend (or some stranger who will become a friend, or perhaps his dealer) to arrive shortly.
“So tired of waiting for you” implies that Ray knows it’s pointless, and that you’re always going to keep-a him waiting.
It means before. Ten of twelve means it’s 11:50.
I take issue with davekhps’ example, though - no one would say fifteen of, but quarter of. Other rules for its usage are that it’s only used with increments of five, and only between twenty and five: no one says “thirteen of eleven” or “twenty-five of three.”
I heard “waiting on” used where I would have used “waiting for” when I was in college. The town where the college was located had a high German immigrant population, and I was told that “waiting on” was based on German prepositional structure. Supposedly (and I never tried to confirm this, so I can’t vouch for it’s accuracy) the German phrase that meant “waiting for (someone)” was commonly translated into English as “waiting on (someone)”.
This was over thirty years ago, and I may not be remembering this correctly, so feel free to point out how wrong I am. 
My family background is German and they never said “waiting on” (although they were not recent immigrants). Also, the parts of the U.S. where “waiting on” seems to be most prevalent do not have a lot of Germans. You may be right but I don’t think it would be the most general explanation.