I think coming out of the petalled lips of five year olds “Thank you for having me etc” is delightful and useful early-years training in politesse, but in grown adults it’s a totally ridiculous affectation that has sprung from nowhere, and does not dignify adult conversation.
When can we expect the re-emergence at dinner parties of a sing-song rendition of “Please may I leave the table?” 
Don’t forget to put your hand up first.
That reminds me of the time when my son was 4years old. He had played happily all afternoon with my friend’s daughter. As we left I said’say thank you to Lindsay for a lovely time.’
He piped up. ‘But I haven’t had a lovely time.’
Luckily my friend burst out laughing.
Honest Lad 
Yes, just occasionally people need to listen to themselves, to realise how bad it sounds…These things follow a fashion …eg …‘whole new ball game’…‘know what I mean’…‘everything happens for a reason’…‘at the end of the day’…‘I turned around and said’…‘running around like a blue arsed fly’…‘it is what it is’…I have a well educated relative, who frequently uses thes in multiple combinations !
They don’t all irritate me (even I use ‘Whatever’…and 'am I bovvered ?..occasionally…)…but I suppose I do so consciously, so it’s a bit different…
I have noticed that when people are being interviewed on TV, it is now commonplace that people will start their responses with ‘So’…which I really don’t like…'I really , really don’t, REALLY ’
How about “scary”? Amongst adults, grown adults, this pathetic baby-word has completely usurped "worrying, frightening, alarming, terrifying, horrible, awful, concerning, troubling, distressing and a score of other nuanced adjectives.
Do grown adults usually feel ‘scared’? I thought this word applied to bogeys under the bed, spiders in the bathroom, or paddling in the sea up to your knees without holding Daddy’s hand…
Gawd help us if this infantile mentality is what the Brits have degenerated to 
It’s really, really scary! 
… another annoyance is when people incorrectly refer to “a learning curve” which when correctly used refers to a rate of learning decreasing over time - however it seems to be too often used to refer to learning something new…
[rant over]
I’m not sure that is what I would think of when hearing the phrase “learning curve” - I would assume that one is talking about the level of expertise, skill or familiarity with a task or subject as one learns or gains experience over time - in fact that is pretty much what Wikipedia thinks as well1.
Graphically it follows an S-shaped curve:
Initially it seems like a lot of effort gets you very little reward, then things start to fall into place and finally you become fully proficient and there is only a little room for further improvement with time.
Are you talking about age-related cognitive decline? While this is a real phenomenon, outside of disease processes like Alzheimer’s there is evidence that it is a bit over-hyped and older people can learn just as well as “young-uns” because greater experience in the task of learning itself offsets the age related changes in ability to learn.
1] I realise that Wikipedia is only slightly more reliable than the Internet at large - i.e not very.
Hi Paul -
I think that it is more like this:
Where the rate of learning initially is far higher than later on.
Now listen out for how many times it is used incorrectly!
That is not, typically, my experience when learning a new skill but it is going to be quite variable depending on what you are trying to learn and the individual who is doing the learning.
As to using it incorrectly - maybe but language is a fluid thing and usage changes over time.
Well to be honest…(lol…!) I can’t really think of any expressions that really irritate me… x 
I did once gain a particular fondness for the word “debriefing” when up against a lieing purported authority…and I found it a source of great satisfaction how easy it was to show they had been “caught with their pants down…” x 
Must admit, lol gets up me snitch Helen, “but I still like you” 
LOL…!
Must admit I’m not a fan of “LMFAO” or “PMSL”…but really don’t take offence at anyone who uses them…if something is really funny then me and my kids tend to go for “LOLOLOLOLOLOL…” x
For an ex M N man I am naive, no idea what they mean Helen
I thought I invented LOLOLOLOLOLOLOL in 1999.
Kids these days, no sense of history, no respect for their seniors 
Isn’t that one of Pliny the Elder’s’s complaints?
Attributed to Socrates by Plato, too, a bit earlier. The elder Pliny’s sense of history got him killed, well his curiosity about a contemporary event did.
I suspect that it has been said of just about every generation of youth by just about every generation of older folk 
