I read somewhere that Billy Preston got very annoyed with Paul during the "Let It Be" recording sessions, because Paul was such a perfectionist, whereas Billy just like to play how he "feels" at the moment.
There's a scene in the movie "Let It Be" that shows Paul trying to explain to George a very subtle electric guitar lick he wants, and Paul has to keep explaining it over and over and over and over..... you can tell George's patience is wearing thin, but nevertheless George keeps trying...
I prefer the Paul perfectionist style in music, myself.