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.

“We were just about the walk away to listen to a take when John leaned his guitar against the amp. I can still see him doing it. He really should have turned the electric off. It was only on a tiny bit, and John just leaned it against the amp when it went, ‘Nnnnnnwahhhhh!’ And we went, ‘What’s that? Voodoo!’ ‘No, it’s feedback.’ ‘Wow, it’s a great sound!’ George Martin was there so we said, ‘ Can we have that on the record?’ ‘Well, I suppose we could, we could edit it on the front.’ It was a found object, an accident caused by leaning the guitar against the amp.”

In Anthology, Lennon explained that he wrote “I Feel Fine” with the backing guitar riff. However, he had trouble writing a song around it and believed what he wrote was “lousy.” However, when The Beatles played it, they thought it sounded great and selected it as an A-side single with “She’s a Woman” as the B-side.

“I wrote ‘I Feel Fine’ around the riff, which is going on in the background. I tried to get that effect into practically every song on the LP, but the others wouldn’t have it,” Lennon explained. “I told them that I’d write a song ‘specially for this riff. So they said, ‘Yes, you go away and do that,’ knowing that we’d almost finished the album. Anyway, going into the studio one morning, I said to Ringo, ‘I’ve written this song, but it’s lousy.’ But we tried it, complete with riff, and it sounded like an a-side, so we decided to release it just like that.”

While John Lennon had little confidence in “I Feel Fine”, it’s fortunate that the rest of The Beatles liked it. The song was heavily praised by critics and audiences alike and performed incredibly well commercially. It became a No. 1 hit in multiple countries, including the U.K. and the U.S. In the U.S., it topped the Billboard Hot 100 for three weeks, becoming the sixth Beatles single to reach that spot in the U.S.