Oh boy do I hate to hear people say PIN nunber, or VIN number for that matter. Personal Identification Number number?
What are some other despicable phrases you hear on a normal basis?
“ATM machine.” Drives me bonkers.
MTCN number…money transfer control number number. Gah!
Ooohhhh tautologies, one of my pet peeves…
“At this moment in time…”
“Stupid idiot”
“CAD design”
This is just a WAG guess 
on my part, but “PIN Number” is probably called that because people could get confused with “pin”, like a pushpin,* so adding “number” to indicate you’re talking about the four- or five-digit code for banking or other security purposes. If only “PI Number” had caught on then there wouldn’t be a problem. Can’t explain “ATM,” though.
*Note: This may seem dumb, but remember that most people are dumb.
So, there is a word for those.
Or how about that TV show Navy NCIS AKA Navy Navy Criminal Investagative Service.
Yeah, I don’t know. I think I’m more bothered by people that are extremely bothered when someone says “PIN number” than I am bothered by the saying of “PIN number” itself.
Here’s how I think of it: sure, “PIN” does stand for “personal identification number,” so PIN number really is personal identification number number, but that doesn’t really matter all that much. It just so happens that the number you use at the ATM has come to be known as your PIN number. So that’s its name, PIN number. What PIN stands for is absolutely inconsequential.
What about “SCUBA gear”? SCUBA stands for self-contained underwater breathing apparatus, and “apparatus” means essentially the same thing as gear, so why doesn’t that one bother you? Probably because it’s just called scuba gear.
Language doesn’t have to be logical, it just is what it is.
As an annoying pedant, I’ll occasionally reply to sentences containing “PIN number” or “ATM machine” with “Personal identification number number?” or “Automatic teller machine machine?”
Makes ME feel better, at least.
Innocent bystander: “I forgot my PIN number for the ATM machine!”
[Is promptly beaten to death by Eve and King Friday]
That sort of explains how I’ve gotten over RBIs. I used to always say RsBI. But then I came to the conclusion that a run batted in is called an RBI because that’s what it’s called, not because of what it stands for.
This phenomenon is known as Redundant Acronym Syndrome, or RAS syndrome for short.
Kmarts or Meijers**
It is singular, unless you go to two Kmart/Meijer in one day. Then it is Kmarts. size=1]And I don’t know where, if at all, to put the ’ . [/size]
This drives me completely batshit.
A work-related redundancy:
FOD damage
(FOD = Foreign Object Damage)
So you end up with “Foreign Object Damage damage.”
Argh.
Department of Redundancy Department?
Surely they’re Superfluous Unnecessary Tautologies?
… because if you say “PI number” some smart ass is bound to start reciting Pi to some ridiculous number of digits?
My current irritation is “ISP Provider.”
Oh, there’s plenty in computing:
GUI interface
GPL licence
Outdated, but DOS Operating System still grates
NTFS file system
I mentioned this thread to my wife and she immediately came up with
SAT Test
GCSE certificate (one for the English)