What Paul McCartney had to say about I Feel Fine :
The song itself was more John’s than mine. We sat down and co-wrote it with John’s original idea. John sang it, I’m on harmonies and the drumming is basically what we used to think of as What’d I Say drumming. There was a style of drumming on What’d I Say which is a sort of Latin R&B that Ray Charles’s drummer Milt Turner played on the original record and we used to love it. One of the big clinching factors about Ringo as the drummer in the band was that he could really play that so well.
Paul McCartney
Many Years From Now, Barry Miles
As quoted here :