I keep seeing these words crop up in some forum posts ???!!!

[tapid]

STRESS is the most overused word in English dictionary, . Apparently everyone s got it.

[Marco]

Lol - not me. Zero stress here at Marco towers!

Marco.

[tapid]

Lol - not me. Zero stress here at Marco towers!

Marco.

Yeah, I know that old chap !

[Vince]

Down size......ha ha.......never happens
Reduce box count.....I'm sure the things breed.

[Audio Al]

Another saying I dont understand is " the speakers don't work in my room "

I am fortunat to have a extensive speaker selection , They ALL work in my room thats not huge and they sound to my ears better firing across the width of the room

[ianlenco]

.......and another, especially on ebay is "rare" when the object is patently not rare

[Len Co]

Somewhat tangentially, every politician who appears on my telly starts every discussion with the words ‘I/we/my party/Jeremy (delete as appropriate) has been very clear on this’.
Then proceeds to use a similar phrase at regular intervals throughout the piece.

OK, guys and gals, it’s understood from now on, leave it out and take the opportunity to stick a few more-entertaining untruths in, we’re fed up of this one.

[Beobloke]

.......and another, especially on ebay is "rare" when the object is patently not rare

Following on from this, it is also a fact that when something is described as "Rare - the only one on eBay", not only will there be four more of them listed at the same time, the others will all be cheaper and in better condition.

[Joe]

'Reluctant sale' = Can't wait to get shot of the bastard thing.

'Priced to sell' = Previously listed at twice the price

'Customised' = Broken

'Rare example' = Most have been binned because they're shite

[Gaz]

.......and another, especially on ebay is "rare" when the object is patently not rare

Very true, I used to see it a lot when I had an old Golf GTI, people advertising parts on Ebay as rare that are freely available from GSF or ECP.
You also saw "uber rare" that usually meant also freely available but the seller was adding "scene tax"