8. John Lennon - 'Instant Karma'
A few months before the public learned that the Beatles had broken up, John Lennon woke up with a new song in his head. "I wrote it in the morning on the piano," Lennon told Rolling Stone in 1971. "I went to the office and sang it many times. So I said, 'Hell, let's do it,' and we booked the studio, and Phil [Spector] came in, and said, 'How do you want it?' I said, 'You know, 1950s.' He said, 'Right,' and boom, I did it in about three goes or something like that. I went in and he played it back and there it was. The only argument was that I said a bit more bass, that's all, and off we went." The song was in the can the very day it was written, and just 10 days later, it appeared on store shelves. It was a huge hit all over the world.