The Beatles were excellent at deciding when a single should be released as an A-side vs. a B-side. Sometimes it was hard to tell if a song was an A-side before it was played. John Lennon wrote one song for The Beatles that he felt was “lousy,” but the band’s version of it was good enough to make it an A-side single. “I Feel Fine” was written by John Lennon and released in 1964 by The Beatles. The track was considered revolutionary as it’s one of the earliest rock songs to include amplifier feedback in the recording. While The Beatles were innovators in discovering new recording techniques, this happened accidentally. In Barry Miles’ Many Years From Now, Paul McCartney admitted that the feedback happened after Lennon leaned his guitar against an amp.
Source: Ross Tanenbaum/cheatsheet.com