I found this article at Snopes interesting: Guitar Man.
Back in the 80s when I was an aspiring keyboardist, I would go to Hastings sometimes and buy the piano score books to albums and groups that I liked. One of the books I bought was for Styx's Paradise Theater. Remember the beginning of the song "Snowblind"? It has a bass line with a sort of arpeggiated keyboard riff over it. I tried and tried to get the hang of that piece, but never could. I didn't seem to have enough hands.
Then one day I bought a video of them in concert, and they played that song. The bass part, of course, was played by Chuck Panozzo on his bass guitar. The keyboard part was, of course, being played by Dennis De Young on a synthesizer.
"WTF?!" I thought. "This part takes TWO professional musicians to play and I'm supposed to play both parts myself?!"
I did learn to play "The Best of Times" and could crash through "Half Penny, Two Penny" fairly well, but did I ever master "Snowblind"? Nope.