WikipediaThis is perhaps another aberration in my ranking as it is a very nice song and all the more impressive since it is one of McCartney’s first original contributions to the Beatles recordings, appearing as the B-side to Love Me Do. Apparently it could not be considered as a potential A-side since it shares its title with an earlier song. I guess that makes explains what would otherwise have been a puzzling decision, because in my view P.S. I Love You is, unambiguously, the better song.
P.S. I Love You strikes me as very original musically – especially the verse. It does not use one of the standard rock, blues or pop chord progressions (in fact it includes a fancy modulation), and it uses harmony vocals in a distinctive way, apply them only to alternate phrases in the verse.
McCartney is pretty modest about the song, describing the letter theme as one of the “easier” themes to “hang a song on”. Over and over again, I find both Lennon and McCartney tend to downplay their originality, but when they think something is derivative it tends to be at quite a conceptual level. Yes, you can “easily” write a song about a letter. But it is not easy to write one that already sounds like an old standard or a stone-cold classic when you are 20.