With respect: re the former -- in my understanding, "Good on..." has been for well over a century, established Australian English as a congratulatory phrase: the way that is said there, what elsewhere is more usually expressed as "Good for...". It may not be patrician English, but it is for sure linguistic "standard operational procedure" in that part of the world. I'd think that Aussie participants in the forum would concur here.
And, equally with respect, many of the other phrases and words mentioned in this thread are "established" and "standard operational procedure" in various areas as well. I've seen quite a few that, while may not be favored in some parts of the US or world, are absolutely correct in my area. And I'm assuming that's true of ones that irk me as well.
I'll use the word "Antipodean" -- I'm in the UK, so Australia and New Zealand are our geographical antipodes. The crux of the thing for me is, that (as touched on in more recent posts), "trendy" expressions, for most of us, imply spoken or written stuff which has shown up only recently. For most of my 64 years of life, I've been aware of "Good on..." as an Antipodean congratulatory expression (and to me personally, rather a nice one); so to me, very far from new. It so happens that I'm not annoyed by the expression itself, or by its being borrowed by other peoples. Of course, everyone is free to find any form of words, irritating !
(MariaE, thanks for confirmation from the Antipodes.)