“John and Paul related to each other as peers. Theirs was not a big brother/ little brother relationship (as seemed to exist between John and George), despite the fact that Lennon was a year and a half older than McCartney.
They clearly had the closest friendship within the Beatles, at least at first, but they couldn’t have been two more different people.
Paul was meticulous and organized: he always carried a notebook around with him, in which he methodically wrote down lyrics and chord changes in his neat handwriting. In contrast, John seemed to live in chaos: he was constantly searching for scraps of paper that he’d hurriedly scribbled ideas on. Paul was a natural communicator; John couldn’t articulate his ideas well. Paul was the diplomatic; John was the agitator. Paul was soft-spoken and almost unfailingly polite; John could be a right loudmouth and quite rude. Paul was willing to put in long hours to get a part right; John was impatient, always ready to move on to the next thing. Paul usually knew exactly what he wanted and would often take offense at criticism; John was much more thick-skinned and was open to hearing what others had to say. In fact, unless he felt especially strongly about something, he was usually amenable to change.
There were so many differences between them, I often wondered what it was that made them such great friends, unless it was simply that opposites attract.” (Geoff Emerick, “Here, There and Everywhere, My Life Recording The Music of The Beatles”)