"Day Tripper" was written under intense deadline pressure. Hence, it might have been John's idea to lift the progression from "What'd I Say," as they needed one more song to have "Rubber Soul" in the shops by Christmas. "ERIC CLAPTON...has graciously consented to speak to you in several critical areas,"* @ 3:30 being the relevant one here:
...I guess George must've told him? As for "Come Together," @ 1:00 here: ...Lennon sings "here comes old flat top..." which sort of clued me in. I can hear Paul's bassline over the progression to this tune. Of course, this is all speculation. Part of the fun, you see--nobody told me. Strange days indeed. Uncle Albert/Admiral Halsey has a nice sad/happy melodic juxtaposition to it. Even without the lyrics. And of course, "Another Day" is insanely catchy, and "Daytime Nighttime Suffering" is all right that one... [size=7]* with apologies to Frank Zappa.