This falls in the category of, why did nobody ever tell me about this?
You know I'm a Beatles fan, but my knowledge of post-Beatles is pretty much limited to the first subsequent decade. I know a lot of Lennon's later work, some of which I like ("Watching the Wheels" is my favorite of his solo songs), I've heard some of Harrison's, I know a lot of McCartney's work from the Wings period, and while I enjoy some of it, the oft-noted treacliness is also really there.
After that: well, I wasn't doing anything so radical as to buy anybody's new albums myself, so at the time I had to depend on what I might overhear on the radio, and the early 80s was the one period in my life when I actually listened to pop radio of my own volition.
In 1982, Paul McCartney released two songs, both collaborative, that were all over the radio. You didn't have to turn it on yourself to hear them. They were the gawdawful "Ebony and Ivory" and the even more execrable "The Girl Is Mine." These songs were evidently popular, because they were unavoidable for a while, but they were so bad as to lead me to conclude that, whatever shreds of his talent he'd retained in the 70s, he had now entirely lost.
And I've paid no attention whatever to his more recent work since. (Reviews I read of his ventures into classical did not encourage exploration.)
Until now. I found this little article giving the author's choice of Sir Paul's best post-Beatles songs. The first four, from the 70s, I knew. I had never heard, or even heard of, any of the subsequent six.
What throws me is not just that they're all at least OK and some are quite good, but that the very best of them, a song that instantly hit my list of favorites, is also from 1982 and in fact from the same album that "Ebony and Ivory" is on. Why did I never hear this at the time? Why had I never heard of it in all the interim? True, I don't go seeking them out, but lots of things that appeal to me a lot less track themselves across my path without my volition; why did it take this one thirty years?
(Of the links at the bottom of the page to similar lists, I have so far explored those of the Beach Boys, which confirms my opinion that they only ever had about two-and-a-half good songs, one of which isn't even on the list, also that they could not sing; and Richard Thompson, whose work I like a lot better, to the extent that I can grouse over the choices and object that no list omitting "When the Spell Is Broken" and "The Poor Ditching Boy" can possibly represent his best.)