Thanks to Soup for a most enjoyable puzzle.
Very tricky in places but there's enough low hanging fruit... anagrams, hiddens etc., to stop one getting stuck.
Bit of a weird coincidence - I was listening to a YouTube selected 'mix', which started off with Neil Finn (Crowded House), then Roddy Frame (Aztec Camera) and then, just as I started 13a, who should come on but Mr Goodbye my Lover himself - (yes, I know, the clue says 'to' not 'my', but still)
Wait, there's more.... a couple of weeks ago YouTube suggested I check out a US comedian called Dane Cook. I hadn't heard of him and, to be honest, his story is more interesting than his routine is funny but, by all accounts, he was the person who started the whole 'Karen' thing, coining the phrase in one of his bits.
It's a US term so maybe Geeker can add something.