Well it wouldn’t be an alphabet of crap if the Beatles did not make the cut. PS I Love You comes from the stage of their career when they were not being feted as the single most important cultural event of the twentieth century. The beginning of their career, on the ironically titled Please Please Me (my name for the album is Please Destroy It). This part of their career was notable for being crap with simpler arrangements, and songs which rather than have several verses often just repeated them over and over again.
The conceit here is that the hero is leaving his girlfriend for some time and is writing a note to tell her how much he loves her. Which is why it is a bit odd that he leaves it to the postscript to do just that. Equally it is possible that since the writer is a Beatle, the tortured similies and metaphors with which the idea was being put across in the body of the letter needed a postscript for fear that she would not understand them. After all, how smart could she be going out with a Scouser with a bowl haircut? And just in case it is unclear who they love, they say it twenty six times in the song. PS, they love YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU. YOU.
Get the message?