Interestingly, my Funk and Wagnalls has the definition of “to pan out” as “to succeed”.
Either the phrase was so common that the Establishment threw in the towel, or there is something else going on with the gold-panning meaning. Maybe “to pan out” meant that they struck it rich and no longer had to pan for gold?
Ethilrist, do you have a cite? I’ve done this debate before more than once, and have never seen a trustworthy source with goldmining the usage you describe: a river getting “panned out,” meaning that there’s no more gold. I’ve never come across a modern use of the phrase “panned out” to mean something being exhausted, outside of—er, well, let’s just say—not-NYT-caliber websites cited in aforementioned debates,
In every dictionary I’ve seen, to pan out means to get gold out of the river by panning, so panning out is a good thing.
“On the ground,” or “the situation on the ground.” It usually prefaces an account of people being killed, or about to be killed. It might make sense if one had to differentiate between it and the situation in the air, or underwater, but since most things do happen on the ground it’s an idiotic expression.
Dude! I’m not the one saying it! When I reference a losing battle, I mean I’m gradually coming to accept that I just need to let it go and not cringe inside when other people say it, because it’s a mistake that’s becoming more prevalent every day.
“For real though”. What does this imply, that the rest of the time you talk about mostly made up things? God that drives me nuts.
Also the phrase “You know what I mean?” is fine when used if you just explained something perhaps difficult, or of unclear definition, but it’s asinine when used after every other statement. As in “I was over at dude’s house, you know what I mean?” Yes, you were at the dude’s house. I followed that part.
Apparently I’m fairly alone in my distaste for this term; I had to go several pages deep in a Google search before I found a couple examples:
One site that showed up in google but got a 404 error: “Area mines produced nearly two million ouncesof gold before panning out in the 1930s.”
By 1908 the gold started panning out.
There were numerous examples, however, of people thinking that “panning out” was a good thing. Bah.
I use that one because it makes my co-worker angry (not cow-orker) especially when the day is only about 8 years ago 
Phrases that cause me to want to kill are:
Moving forward…
At the end of the day…
Touch base…
Over… use… of… elipses… (I mean, I love those little dots, but they are like good gin, overuse will give you a headache.)
You’re pronouncing it wrong. Its “not for nuttin”. 
I wish I could remember Dom Irrera’s schtick about this and other spressions.
Oh yeah, I thought of two more:
A stitch in time saves nine. (I don’t really understand the point people are trying to get across by saying it. If anyone else does, explain it to me.)
Six in one, half a dozen in the other. (It’s just pointless.)
Three years ago, my daughter graduated from high school, and seeing how it was the largest graduating class EVER in the history of the school district, it gathered quite a turn-out, including the press and the Mayor. The bigwigs stand up and give their speil and all, when it comes time for the valeditorian (did I spell that correctly?)–who, by the way, NO ONE can figure out how this ditz every managed to get chosen for valeditorian since she didn’t have a lick of sense, common or otherwise. Anyho (ha, I read prior posts!), she’s in the middle of her speech (which was poorly written and difficult to follow) when she messes up. In front of the press, the Mayor and everyone in the city’s grandmother and extended family, she giggles and says, “My Bad!” You could hear the collective moan as hundreds of family members and friends are simutaniously humiliated. Ever since, every time I hear that phrase, I want to smack someone.
It means, “Fix it now, don’t procrastinate or you will have nine times the work down the road.”
“…what with this, that, and the other.”
A coworker says this all the time. It makes me crazy.
Of course, he also starts his stories too soon. You know the type: They give you details about what they ate for breakfast, lunch, and dinner before getting to the point of the story which is what they saw on TV. He’s a premature anecdotaler.
Mostly, a couple of seconds:
*Not for nothing * - this is the one I would have listed had it not shown up already. This is the most useless, meaningless phrase I’ve ever heard in my life, and it’s everywhere. I’ve yet to hear this used in any way that matters. Garrgh this one is horrid.
My bad - it just sounds idiotic. And Civ III really pisses me off because if I have troops in Montezuma’s territory, and he calls me on it, the game has “My bad <your troops will move automatically>” as one of the responses. I feel pretty confident that if Abe Lincoln had ever heard himself muttering “My bad”, he would have had himself arrested or something. [I posted a thread the other day mentioning that Montezuma told me at the end of the game that “All your base are belong to us.” I’m gonna track down the dialogue writers and have a word with them one of these days.]
Back in the day - What really annoys me is that I usually hear this coming out of the mouth of a 16 year old, for whom “back in the day” was two weeks ago. Fer cryin’ out loud.
And to add my own: 24/7. If you’re doing anything 24/7, you’re not cool, you’re OCD, and you sound ridiculous to boot.
Here is what Dictionary.com claims is the origin of Pan Out.
It doesn’t seem to have anything to do with Gold.
Whenever pop culture brings a new phrase into use and everyone starts using it I get annoyed. I might start using it myself, I’ll admit, but once everyone seems to be getting in on the act I abandon its usage and get annoyed at the people who still think it’s clever and original. Recent examples: “Is that your final answer?” (Who Wants to be a Millionaire), “You are the weakest link… g’bye!” (Weakest Link) and “Whassaaaaaaap?!” (Budweiser commercials).
Another phrase that grates my nerves is, “as all get-out.” When people say this I get annoyed as all get-out. This makes absolutely no sense whatsoever!
When someone means, “sure, go ahead” but chooses to say, “Knock yourself out!” instead, it makes no sense to me. I tend to interpret this phrase literally (yes, literally) whenever I hear it, so I am left to wonder why would I deliberately knock myself out?
Stitch in Time - if your pocket is starting to rip at the top, putting one stitch in now will prevent you from having to put 9 stitches in at a later time.
Six in one - The phrase is actually “Six Of one, Half a dozen of another” it means you are comparing two things that are basically equal:
Shall we take 15 north or 81 north to Daneville? “Six Of one, Half a dozen of another wouldn’t you say? Both will take roughly 3 hours.”
***“Be that as it may” * **
Grrrrrrrrrr. My boss has the annoying habit of ending every single subject with this phrase. He thinks he’s being smart, but just comes across as a big idiot.
“My kid is going to college. Be that as it may, tuition is very expensive. Be that as it may, how’s your day going?”
ARRRRRRRRRRrrgggggggg.
It’s all good!
I hate “sweet” as an exclamation. As in:
“You just won a million dollars!”
“Sweet!”
“My bad” doesn’t bother me in moderate amounts. More grating, however, is “just kidding”. As in:
“Today is Friday.”
“No, it isn’t. It’s Thursday”.
“Oops. Just kidding.”
In New Jersey, people use “Whahappened?” when they really mean “I didn’t catch that” or “Beg your pardon?”
“Tomorrow the sun will come up.”
“Whahappened?”
It’s crazy, I tell you!
Annoyances:
MW goes on to reflect that others commentators feel the same as MysticMilt.