The Beatles' Sunday Driving

A few months ago, I realized that the Beatles' "Day Tripper" and "Two of Us" both contain the phrase "Sunday driver" (or, as it appears in "Two of Us," "Sunday driving").  Recently, I transcribed and compared the lyrics.  There isn't much that would indicate that "Two of Us" is supposed to a sequel of sorts to "Day Tripper," but they are rather like two sides of a coin.

The lyrics of "Day Tripper" aren't super clear, but it seems to be about a relationship that the speaker/singer isn't going to continue, as the girl is flighty.  One repeated section starts with "She was a day tripper."  The third repetition includes the "Sunday driver" phrase:

She was a day tripper
Sunday driver, yeah
It took me so long
To find out
And I found out

On the other hand, the speaker/singer of "Two of Us" seems to mention only himself and his companion (each verse and chorus contains either "Two of us," "You and me," or "You and I") and their impending domestic return ("We're on our way home").  "Sunday driving" occurs in the first verse:

Two of us riding nowhere
Spending someone’s hard-earned pay
You and me Sunday driving
Not arriving
On our way back home
We’re on our way home
We’re on our way home
We’re goin’ home

"Day Tripper" is all about how there isn't a relationship, and "Two of Us" is about how there is.  Both contain "Sunday driving," but I think it's more significant that the girl in "Day Tripper" goes alone where the couple in "Two of Us" is together.

Apparently, "Day Tripper" is mostly a John Lennon song, and "Two of Us" was written entirely by Paul McCartney, but I don't know how/if that affects that common phrase.