Let me tell you a bit about the life of John Lennon. His parents were never together, and he and spent much of his childhood being partially raised by his mother, mostly raised by others in his extended family, especially his aunt. His mom was in and out of his life, but she bought him his first guitar at age 14. At age 17, just as they were starting to reconnect, his mom was hit by a car and killed. He had been playing in a band with a kid in town named Paul McCartney. Paul's mom had passed away too. Together, they poured their disoriented lives into their music.
John played guitar well enough, but not fantastic. What he could really do was sing, and lead a group - and write songs using just the basic guitar chords he taught himself. He made those basic chords count over and over.
The insanely beautiful verses of "A Day In the Life" consist of the most basic open chords you can play on a guitar: G - b - e - C - e - a
Those chords had existed for thousands of years before John Lennon came along.
Five years deep into his run as part of the biggest band in the world, this kid from Liverpool took those chords and put his ominous, exhausted voice over the top of them, and created a song that was the musical equivalent of landing on the moon.