...the lyrics to "Why Don't We Do It In The Road" were penned by McCartney, and while he could fashion great lyrics on occasion, he occasionally succumbed to bananlity, as in this later lyric after the Beatles broke up:

"Someone's knockin' at the door
Someone's ringing a bell
Someone's knocking at the door
Open the door, let 'em in." - from an insipid McCartney/Wings tune

Or

"Some people want to fill the world with silly love songs
What's wrong with that, I'd like to know
'Cause here I go, again." - from another insipid McCartney tune