One could easily make a case for almost the whole of Sgt. Pepper's Lonely Hearts Club Band as being a "greatest" bass performance.
The Beatles, led here by McCartney, ushered in a new realm of songwriting and production aesthetics, forever changing the concept of the record album experience - all of which was reflected in the group reaching new levels of musicianship.
McCartney's own Getting Better neatly encapsulates the breakthroughs he made as a bassist in 1967. With an entire track of his own on which he could experiment with overdubs (EMI Studios had graduated to four-track), Paul serves up a lively, propulsive rhythm, bolstering the effect of the cracking snare and popping off with effective slides.
Humorous, carefree, bright and sunny - like the Summer Of Love Sgt. Pepper helped create.