Short answers, pulled from the story.
George Harrison wrote the song I Me Mine on the 7th of January 1969 during the second week of Beatles rehearsals at Twickenham Film Studios. The atmosphere inside west London was thick with acrimony as the group argued over their future direction.
John Lennon ridiculed the song and joked that a collection of freaks could dance along with George's waltz. He told Harrison to get lost because the group only played rock and roll with no place for a Spanish waltz.
The Beatles performed the track forty-one times during rehearsals yet the recording lasted only a minute and a half. McCartney and Starr provided enthusiastic support according to author John Winn but Lennon mostly opted out of the process.
The verses of I Me Mine are written in A minor while the chorus shifts to A major creating a parallel minor major contrast. This technique had been employed by Harrison in his 1968 songs While My Guitar Gently Weeps and Savoy Truffle.
On the 1st of April Spector overdubbed a twenty-seven piece string section six brass players and additional drums by Starr. These additions became the final overdubs on a Beatles track before the group broke up in April 1970.
Harrison titled his 1980 autobiography I Me Mine after the track making it the first autobiography by a former Beatle. The title served as an ironic comment on the falseness of adhering to a self focused perspective according to Harrison's foreword.