So many, but this'll do for starters...
Once you get to my age most things are annoying at some level, but one that really pisses me off now...

People who say "Say Again" when they mean "Pardon".

Let me explain. Once upon a time we used to say "pardon" or "I beg your pardon" to indicate we hadn't heard what someone had said. The inference was that we (the listener) were at fault for mishearing what was said. Now people say "Say again" and imply there is something wrong with the speaker's diction. It's arrogant and 'Thatcherite" in it's assumption that it's someone else's fault, not our own.

A small thing, but then the small things are often the most annoying...
(Mr Steve is jobless and fancyfree!, Fri 2 May 2008, 10:28, 4 replies)

What?

( enoughblueskyforsailorstrousers, Fri 2 May 2008, 10:31, closed)

I do this
And I don't think it's Thatcherite - it may be from radio useage way back in the past but it's stuck.

And with crappy mobile signals abounding, it's come back.
(osok Rebel without a clue, Fri 2 May 2008, 11:06, closed)

In Australia at least..
...it's an Army thing. I started saying it when I worked at the Department of Defence.
(apeloverage committed the vile act of onanism on, Fri 2 May 2008, 11:13, closed)

I use it from my time operating radios in the army cadets (otherwise known as "signals")
In the military, the phrase "repeat" is an artillery command, so if you missed what someone said on the radio you say "say again, over". That's the only reason, nothing to do with Thatcher.

Oh, and "over and out" is a nonsense.
( emvee cruor deo cruoris, Sat 3 May 2008, 13:41, closed)