Do you really care? We have all seen Pete's signature arm flail and well lets face it it looks damn cool. Guitarists today rip it off all the time but how did that start?
Pete actually took the time to explain its origin. Contrary to everything else in his life this was not brought on by some sort of molestation or abuse. The Late Show with David Letterman is actually how it came to topic
"We were a little R n'B band… and we supported the [Rolling] Stones on two shows; they were brand new, they were young, they had one hit with Chuck Berry's 'Come On,'" explained Townshend. "As the curtain opened, Keith Richards is kind of doing this (demonstrates windmill move). I thought it was part of his thing."
"Anyway, a couple of weeks later," Pete continued, "we support them again at a little club out in south London, and I'm watching carefully – waiting – and he doesn't do it. So, I go up to him afterwards and I said, 'Keith, you didn't do your arm swing thing.' And he went, 'What?' I said 'you know, that kind of windmill-y thing…you know, your thing.' I can't tell you what he said. So, I picked it up…and I was inspired by Keith Richards in many ways."
So, There you have it, I don't suppose after all these years it even matters. Pete can call the move his own and it is. Are we inspired in our every move and does everything have to have a source or light bulb moment. The Who has been around so long that I think people have just run out of stuff to ask them.
Cool story, Bro. Tell another.

