I’m confused regarding this response, since it seems to more or less say exactly the same thing as Gracer’s post, which I was responding to.
This has been done several times before on the SDMB. I had never heard “another thing coming”, only the “think” version, the first time it came up, and was amazed that anybody could think “thing” was correct. It soon became clear that those who grew up with “thing” were equally convinced that the “thinkers” were brain-damaged. It seems to divide people in a way that it was previously believed only toilet-tissue orientation could manage.
Whatever anyone’s opinion, it is undeniable that the phrase was originally “another think coming”, which is a play on words that is totally lost in the “thing” version.
If you think X, then you’ve got another think* coming. As said to me many times by my mother, with more than a hint of implied threat that said new thinking will be impressed into my skull with what I later came to know as a “clue by four”.
** To which the “thing” brigade (see above) say “but think isn’t a noun”! Well, they might just want to have a think about that in their own time.* 
In the US, at least, it seems to have mutated into “another thing coming”, which is a shame as it loses the whole point of the idiom, but the battle seems to have been lost. In the UK, “another think coming” is still the common phrase. (Similar to how Americans say “could care less” and Brits say “couldn’t care less”.)
It still bugs me, but I have to accept that once an idiom becomes established, people stop noticing whether the individual words make sense, sort of like “head over heels”.
Edit: gracer, I have tried in past threads to explain the humour in the original phrase, but it just doesn’t sink in…
I an very serious when I say I don’t understand how it could be nonsense. A “think” is still a thing! You might not like it, but that doesn’t change the fact that it stands as a meaningful (if vague) phrase.
Yes, they were expecting to get a thing. The thing they wanted was Ron Paul. The thing they got was Barack Obama.
“If you thought that Ron Paul (thing 1) was going to be president, you’ve got another thing (Obama, thing 2) coming.”
But the phrase doesn’t even have to be about a thing, and the “another thing” version of the phrase just feels clunky because it shifts the emphasis away from the “think” which is stressed in the first part of the phrase (the set-up, if you like).
In fact the original phrase wouldn’t really be used as in the example you gave. You wouldn’t use it about an event that has already been decided. The phrase means (as stated verbatim in my dictionary) “you are mistaken and will soon have to alter your opinion”. It’s not that are going to be given something you didn’t want, it’s that it will soon dawn on you how wrong you were to hold that opinion in the first place.
For example, my mother might have said “If you think I’m going to sit here and listen to that, you’ve got another think coming”. What would be the other “thing” in this case? It just doesn’t work.
By that logic, just about any phrase could be replaced by “Thing a thing thing” and still make sense.
When we’ve hashed this out before I’ve expressed the same amazement that people can’t see how much more elegant the original phrase is than the corrupted version. You’d think a lightbulb would click on above their head, but no, they just keep arguing for the other version, the clunky “non-idiom” as I called it in the previous thread.
Still, if you think I’m going to let it spoil my day…
No, that would be “a different thing coming.” You haven’t gotten either thing yet, so you can’t get another one. You can only get another one when you’ve already got one. “You’ve already got a knot on your head, would you like another?” as opposed to “Would you like a knot on your head?” when you don’t already have a knot on your head.
In the original expression, you’ve already had a thought (an incorrect one) and you’re going to have another one when reality sets in.
In your example:
“If you thought that Ron Paul (thing 1 that you haven’t got) was going to be president, you’ve got another thing (Obama, thing 2 that you haven’t gotten yet so it can’t be another but that you will get) coming.” Utterly stupid.
Or:
“If you thought (thought one, that you’ve already got) that Ron Paul was going to be president, you’ve got another think (thought two, the new thought you’re going to have when you face reality) coming.” Makes sense.
Look, in the “think” camp, we have my mother, and her mother before her. They owned dictionaries, read books and spoke English like natives.
In the “thing” camp, we have these guys. They are from Birmingham and wear dog collars in public.
That’s really all the evidence we need, okay? Mum was right. And Grandma too.
Even if we assume that think is more elegant, it’s like putting lipstick on a pig and saying the lipsticked pig is more elegant. Sure, but it’s still a pig. Neither phrase is all that graceful. Anyway, you know who calls thoughts thinks? 3 year-olds and Dr. Suess. Are you a three year-old or Dr. Suess? Then say thing.
Of course it works. In that case the other thing is her NOT sitting there and listening to that.
But “another thing” can mean “a different thing” rather than “a second thing”, if that’s the argument you’re making. “Other”/“different” mean much the same.
As I said, I’m on the “think” side. I just don’t buy this particular argument.
OK, that makes sense. It should be a different thing, not another thing.
But by that logic, shouldn’t it also be a different think rather than another think?
If you think that Ron Paul will be president (first think)
Then you’ve got another think (still Ron Paul) coming.
Obama would be a different think.
Nope. Like I said, you’ve already got the thougtht that Ron Paul will be president. When reality sets in, you’ll have another one and realize that Obama is president.
Also, sometimes the thing is my fist and it’s coming for your face. As in, “If you think you can sit here and chat up my girl, you’ve got another thing coming.”
Nope. Obama is a different think. That knife cuts both ways.
If Paul is one think and Obama is another think, then Paul is one thing and Obama is nother thing.
Unless your saying that another think is different but another thing is repeating the first thing. You’ll have to explain that one to me.
It’s not usually idiomatic to think something when you can patently see it in action. You then know it. So, you may think one thing, but after you prove sorely mistaken, you don’t have another think coming, because you don’t have to think anything, you KNOW you were wrong.
Yes, Obama is a different think. It also another think since you’ve already got the one about Ron Paul.
Using the phrase as the “thingers” would have it, you’ve already got the thought of Ron Paul and expect to get the thing Ron Paul. Since you haven’t got Ron Paul yet, when you get Obama then you have gotten a different thing than you expected - but you haven’t gotten another thing because you never had the other thing. You can only have another thing when you already have a thing.
A cursory stroll thru Google News Archives shows “think” giving way to “thing” most noticeably starting in the 1980s.
“My sister has a Ford Explorer. I have another Ford model.”
That does not imply that I have or have had more than one Ford.
“Another thing coming” seems a perfectly reasonable way of saying “a different outcome to that which you were anticipating”.
Fucking Judas Priest again.
Yes it does, but when prefaced with “If you think X”, which is the phrase we’re talking about, then it comes across as a non-sequitur. It’s a set-up/punchline turn of phrase that suddenly derails and skids to a halt without delivering. It’s unsatisfying. It’s catchphrasus interruptus. It is the Diet Coke of idiom.