I came across another McCartney interview recently.... he said that, in the early days, John was very into starting, and completing songs really fast. Something along the lines of them getting bored quickly if working on one song too long....
Also, I'm not sure that too many people are aware that their first album, Please Please Me, was recorded in just 1 long day of work. If I remember correctly, it was something like 14 songs (not all originals) in like 10 hours....
Incredible.
