6) 'Things We Said Today'
From 'A Hard Day's Night' (1964)
Few things can break apart a relationship more than distance, but not here, where the memories of the declarations of love between Paul and his girl are enough to get him through the long nights that they're apart.
We also see how, as early as 1964, McCartney was turning into a masterful songwriter. The minor key of the verse (driven by an acoustic rhythm part so infectious that the Hollies stole it for 'Bus Stop') reflects his sadness at their being apart, while the bridge switches to a major key to convey his joy with being in love. And George's low harmony is icing on the cake.
Listen to 'Things We Said Today' by the Beatles