These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Don McLean
Covered Up: "And I Love You So" is one of his songs, but has been covered by Elvis and was a hit for Perry Como. In reverse, McLean's "Crying," a huge hit, was originally performed by Roy Orbison.
Genius Bonus: Several. "American Pie" contains references to events and people who were notable in McLean's childhood. Furthermore, "the Levee" is not a levee, but a bar (giving the phrase "but the Levee was dry" an entirely new meaning).
Germans Love David Hasselhoff - "Crying" and "Vincent" did much better in the UK, both reaching #1 (in fact they did better than "American Pie" which reached #2.)
Second Verse Curse: Because "American Pie" was so long, it was released originally on a dual-sided single. Some radios only played Part One.
Weird Al Effect: His kids were such big fans of "Weird Al" Yankovic and have played "The Saga Begins" so much, that even Don has mixed up some of the lyrics of "American Pie" with the parody while performing it.