Sixty-Four, with its easygoing ragtime-y feel and oompah beat, sounds close enough to a trad crowd-pleaser, a bit of harmless between-song hand-jive, or at least a gentle pisstake of the kind of music that the elder McCartney used to do in his own band. Years later, it seemed to fit into the schema of the Sgt. Pepper album, a bright and breezy antidote to the headier atmospheres elsewhere on the record.
Sixty-Four represents the side of the Beatles that everybody likes, typified by all-ages singalong numbers like Yellow Submarine, All Together Now or (ulp!) Maxwell's Silver Hammer (sorry, almost everybody), and of course that side's always been associated with Paul.