The response this to a post annoys and irritates the OP.
There's a heck of a lot of types of comment, style of comment, etc, on social media that irritate the heck out of me, too - "end of" being one of those comments - but there isn't anything we can do about it because social media has evolved to include all sorts and types of posting styles, jargon, abbreviations, etc, etc, and it will continue to evolve and more pert little response methods will be employed. Which will continue to annoy and irritate.
So we'll just have to be annoyed and accept it.
What worries me far more on social media is all the false 'information', all the lies perpetrated by those with an agenda, and those who can't be bothered to filter fact from fiction who spread it further either naively or deliberately; the speculation, the conspiracy theories; the stupid influencers who manage to persuade young people to do stupid stunts that can result in injury or even death to themselves or others; the misogynists like Andrew Tate who spew their poison into the minds of young teens and men; the deluded young women who though medically obese have been persuaded by a politically-correct culture to 'flaunt' their curves because they are "hot babes" and challenge "Karens" and "Kevins" to deny it because, it's alleged, they are simply jealous. - young women who will suffer God-knows what-all health problems in the near future have been persuaded on social media to expose themselves to both ridicule and praise from the equally deluded. And the social media sites that encourage young people with mental health problems to self-harm, where young girls and boys turn to because there is little real, authentic, legitimate help available to them, courtesy of austerity cuts to mental health services.
And that's not even mentioning the social media site owners on whose 'premises' these atrocities are encouraged.
I could go on, but realise I'm ranting away to an audience who may well have become bored with this thread and long gone. However the above worries me far more than the irritating little cryptic this, end of and all the other abbreviated sentiments of approval - or disapproval.